M998A1 Intro/Veh Sys Text - Steel Soldiers

Introduction toVehicle Systems

AM General Corporation5715432

M998 and M998A1 Series Vehicles

MILITARYHMMWV

AM General CorporationTraining DepartmentP.O. Box 728408 South Byrkit StreetMishawaka, IN 46546-0728 USAPhone: (219) 258-6624Fax: (219) 254-2260

January, 1995Revised April, 1995©

Copyright 1995, AM General Corporation All rights reserved

This publication, or parts therof, may not be reproduced in any form, by any method, for anypurpose without written permission from AM General Corporation.

ContentsINTRODUCTION................................................................................................................. 1

TECHNICAL DATA ............................................................................................................. 2

CAPACITIES .................................................................................................................................. 3

CAPACITIES .................................................................................................................................. 3

ENGINE DATA .............................................................................................................................. 3

FUEL SYSTEM............................................................................................................................... 4

COOLING SYSTEM ...................................................................................................................... 4

ELECTRICAL SYSTEM ................................................................................................................ 4

TRANSMISSION............................................................................................................................ 4

TRANSFER CASE ......................................................................................................................... 4

DIFFERENTIAL ............................................................................................................................. 4

SERVICE BRAKE CALIPER (FRONT & REAR) ........................................................................ 5

SERVICE BRAKE ROTOR /FRONT & REAR ............................................................................. 5

WHEELS AND TIRES ................................................................................................................... 5

STEERING GEAR & PUMP .......................................................................................................... 5

WINCH............................................................................................................................................ 5

WINCH DATA ................................................................................................................................ 6

VEHICLE DIMENSIONS .............................................................................................................. 6

VEHICLE CRUISING RANGE ..................................................................................................... 6

MAXIMUM VEHICLE OPERATING SPEEDS ............................................................................ 6

CURB WEIGHT.............................................................................................................................. 6

GROSS VEHICLE WEIGHT (GVW) ............................................................................................ 6

DESCRIPTION AND OPERATION OF MAJOR COMPONENTS ...................................... 7

MAJOR ENGINE SUBSYSTEMS ................................................................................................. 8

MAJOR COMPONENTS OPERATION ........................................................................................ 9

ENGINE OPERATION & EXTERNAL COMPONENTS ........................................................... 10

FUEL FILTER DRAIN VALVE .................................................................................................... 11

PRECOMBUSTION CHAMBER................................................................................................. 11

LOCATION OF THE FUEL LIFT PUMP .................................................................................... 12

FUEL INJECTION PUMP ............................................................................................................ 13

FUEL INJECTORS ....................................................................................................................... 14

DESCRIPTION AND OPERATION OF MAJOR COMPONENTS CONTINUED

FUEL SYSTEM SCHEMATIC ..................................................................................................... 15

HOUSING PRESSURE COLD ADVANCE SOLENOID (HPCA) ............................................. 16

AIR INDUCTION SYSTEM ........................................................................................................ 17

AIR CLEANER SERVICING ....................................................................................................... 18

AIR INTAKE MANIFOLD........................................................................................................... 19

CRANKCASE VENTILATION SYSTEM .................................................................................. 20

EXHAUST SYSTEM .................................................................................................................... 21

EXHAUST HEADERS ................................................................................................................. 22

ENGINE LUBRICATION SYSTEM ............................................................................................ 23

ENGINE NORMAL OIL FLOW SCHEMATIC........................................................................... 24

OIL PUMP DRIVE ........................................................................................................................ 25

OIL PUMP ..................................................................................................................................... 26

ENGINE OIL DIPSTICK LEVEL CHECKING PROCEDURES................................................ 27

COOLING SYSTEM FUNCTION ............................................................................................... 28




FAN CLUTCH FUNCTION

(NOT ON VEHICLES WITH DESERT KITS INSTALLED)...................................................... 32

FAN CLUTCH FUNCTION

(NOT ON VEHICLES WITH DESERT KITS INSTALLED)...................................................... 33

GLOW PLUG OPERATION......................................................................................................... 34

GLOW PLUG CONTROLLER .................................................................................................... 35

GLOW PLUG SYSTEM LOCATION .......................................................................................... 36

MODULATOR .............................................................................................................................. 38

TRANSMISSION DETENT SOLENOID .................................................................................... 39

NEUTRAL SAFETY SWITCH OPERATION ............................................................................. 40

TRANSMISSION COOLING SYSTEM ...................................................................................... 41

M998/M998A1 TRANSFER CASE MODELS 218 AND 242..................................................... 42

M998/M998A1 TRANSFER CASE OPERATION, MODELS 218 AND 242 ............................ 43

DIFFERENTIAL OPERATION .................................................................................................... 44

GEARED HUBS ........................................................................................................................... 45

VEHICLE MECHANICAL SUBSYSTEMS........................................................................ 46

CTIS (CENTRAL TIRE INFLATION SYSTEM) ........................................................................ 47

STANDARD STEERING CONTROL SYSTEM OPERATION.................................................. 48

OPTIONAL STEERING CONTROL SYSTEM OPERATION ................................................... 50

STEERING CONTROL SYSTEM OPERATION ........................................................................ 51

STEERING STOP CHECK AND ADJUSTMENT ...................................................................... 52

TOE IN/TOE OUT CHECK.......................................................................................................... 53

TOE-IN/TOE-OUT ADJUSTMENT ............................................................................................ 54

ALIGNMENT FRONT/REAR...................................................................................................... 55

VENT SYSTEM ............................................................................................................................ 56

VENT SYSTEM ............................................................................................................................ 57

SINGLE PARKING BRAKE SYSTEM OPERATION–SERIAL #1 THROUGH 44824 ........... 58

SERVICE/PARKING BRAKE SYSTEM OPERATION–SERIAL #44825 AND ABOVE ......... 59

SERVICE BRAKE SYSTEM ....................................................................................................... 60

BRAKE MASTER CYLINDER AND HYDRO-BOOST SYSTEM ........................................... 61

STOP LIGHT BRAKE SWITCH .................................................................................................. 62

BRAKE PRESSURE WARNING SWITCH OPERATION ......................................................... 63

BRAKE FLUID ............................................................................................................................. 64

SUSPENSION SYSTEM OPERATION ....................................................................................... 65

STABILIZER BAR OPERATION ................................................................................................ 66

BALL JOINT INSPECTION ........................................................................................................ 67

WHEEL AND TIRE COMPONENTS .......................................................................................... 68

RUNFLAT SYSTEM (BIAS DESIGN) ........................................................................................ 69

RUNFLAT SYSTEM (RADIAL DESIGN) ................................................................................. 70

RUNFLAT REMOVAL (RADIAL DESIGN) ............................................................................... 71

JACKING PROCEDURES ........................................................................................................... 72

WINCH 6,000 LB. (2721 KG) ...................................................................................................... 73

PROPELLER SHAFTS ................................................................................................................. 74

HALFSHAFTS .............................................................................................................................. 75

ELECTRICAL SYSTEM................................................................................................... 76

STARTING SYSTEM OPERATION ............................................................................................ 77

GENERATING SYSTEM OPERATION—60/100 AMPERE ..................................................... 78

GENERATING SYSTEM OPERATION—200 AMPERE ........................................................... 79

BATTERY SYSTEM OPERATION.............................................................................................. 80

WINDSHIELD WIPER/WASHER SYSTEM OPERATION ....................................................... 81

VEHICLE LIGHTS LOCATION AND FUNCTION ................................................................... 82

WINCH OPERATION .................................................................................................................. 83

STE/ICE-R .................................................................................................................................... 84

Introduction to Vehicle Systems

Page 1

INTRODUCTION TOVEHICLE SYSTEMS

FOR THEMILITARY HMMWV

M998/M998 A1 SERIES

INTRODUCTION

Performing maintenance services and repairs on the HMMWV requires an understanding of the basicfunctions of the vehicle components and systems. This program explains the principles of operationand how the components and systems of the HMMWV work together.

AM General Corporation HMMWV

Page 2

SPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEEDSPEED

CAPACITIES

GPM

RPM'sRPM's

Temperatures

TYPES

MODELS

Ratios

AMPERES

TECHNICAL DATA


Page 3

CAPACITIESCooling system .................................................................................................................. 26 qt (24.6L)Engine:

• Crankcase only ................................................................................................................. 7 qt (6.6L)• Crankcase & filter ............................................................................................................ 8 qt (7.6L)

Fuel tank .......................................................................................................................... 25 gal (94.6L)Differential (each).................................................................................................................. 2 qt (1.9L)Transmission:

• Drain & Refill ................................................................................................................... 6 qt (5.7L)• W/Converter ................................................................................................................. 14 qt (13.2L)

CAPACITIESTransfer Case ...................................................................................................................... 3.5 qt (3.3L)Geared Hub ............................................................................................................................ 1 pt (.47L)Steering Hydraulic System .................................................................................................. 1 qt (0.95L)Steering Hydraulic System With Cooler ........................................................................ 1.25 qt (1.18L)Windshield Washer Reservoir .............................................................................................. 1 gal (3.8L)Brake Master Cylinder...................................................................................................... 1.2 pt (0.53L)

ENGINE DATAManufacture ................................................................................................................... General MotorsModel .............................................................................................. (Detroit Diesel Allison) DDA 6.2LType ............................................................................................................ Diesel, Liquid-Cooled, V-8Brake Horsepower ........................................................... 150 hp @ 3600rpm (111.9 kw @ 3600 rpm)Displacement ............................................................................................................... 6.2L (379 cu. in)

Bore ........................................................................................................................10 cm (3.98 in)Stroke .....................................................................................................................9.7 cm (3.82 in)

Compression Ratio ....................................................................................................................... 21.3:1Gross Torque ................................................................................................................ 250 @ 2000 rpmIdle Speed ......................................................................................................................... 650 ± 25 rpmOperating Speed ............................................................................................................ 1500-2300 rpmOil Pressure:

@ Idle Minimum–Normal Operating Temperature ............................................. 10 psi (138 kPa)@ Operating Speed Normal Operating Temperature ............................ 40-50 psi (275-345 kPa)

Oil Filter By-pass Valve .......................................... Opens 16-19 psi Above Normal High of 40-50 psiOil Cooler By-pass Valve ......................................... Opens 9-11 psi Above Normal High of 40-50 psiAir Cleaner, Paper-Clean with shop air or soap and water ..............................420 CFM (Dry Element)


Page 4

FUEL SYSTEMFuel Pump (Mechanical), Lift 4-8 psi ................................................................................ Cam DrivenFuel Pump, Injection .................................................................................................... Stanadyne DB2Fuel Filter ............................................................................................................. Fuel/Water SeparatorGlow Plug ........................................................................................................................12V, Fast Start

COOLING SYSTEMRadiator Cap Pressure .................................................................................................. 15 psi (103 kPa)Radiator Cap Operating Range ................................................................................................ 14-18 psiThermostat:

Starts to Open ................................................................................................................ 190°F (88°C)Fully open .................................................................................................................... 212°F (100°C)

Radiator ................................................................................................................................ DownflowFan .................................................................................................................. 19 in (495 mm) 10 BladeCoolant Boiling Point-50% Glycol/50% water .............................................................. 265°F (129°C)

ELECTRICAL SYSTEMAlternator60 Ampere Prestolite .......................................................................................................... 60 A @ 28V100 Ampere Prestolite/Niehoff ......................................................................................... 100 A @ 28V200 Ampere Prestolite/Niehoff ......................................................................................... 200 A @ 28V400 Ampere Niehoff ......................................................................................................... 400 A @ 28V

TRANSMISSIONManufacture ................................................................................................................... General MotorsModel ............................................................................................................................. THM 400/3L80Type ......................................................................................................................... 3-Speed AutomaticOil Type .................................................................................................................. Dexron II, IIE or IIIOil Pressure................................................................................................. 55-160 psi (379-1103 kPa)

TRANSFER CASEModel M998 ..........................................................................................................................NVG #218Model M998A1 .....................................................................................................................NVG #242Type ...................................................................................................................................... Two SpeedOil Type ................................................................................................................. Dexron II, IIE or III

DIFFERENTIALManufacture ..................................................................................................................... Zexel-GleasonM998 Gear Ratio .......................................................................................................................... 2.56:1M998A1 Gear Ratio ..................................................................................................................... 2.73:1


Page 5

SERVICE BRAKE CALIPER (FRONT & REAR)Model ............................................................................................................................... Kelsey-HayesPiston Diameter ............................................................................................................. 2.6 in (66 mm)

SERVICE BRAKE ROTOR /FRONT & REARModel ................................................................................................................................ Kelsey-HayesDiameter ....................................................................................................................10.5 in (26.67 cm)Thickness .....................................................................................................................0.87 in (2.21 cm)Fluid Type ........................................................................................................................ Silicone Dot 5

WHEELS AND TIRESType ..................................................................................................................................Radial & BiasSize (Radial) .............................................................................................................. 37"x12.50"x16.5"Size(Bias)................................................................................................................... 36"x12.50"x16.5"Runflat Insert, Radial ................................................................................................ One Piece RubberRunflat Insert, Bias .............................................................................................Two Piece Magnesium

STEERING GEAR & PUMPSteering Gear:

• Manufacture/Model ................................................................................................... Saginaw–708• Type ...................................................................Recirculating Ball, Worm and Nut, Variable Speed• Ratio ...................................................................................................................................... 13/16:1

Steering Pump:• Manufacture/Model ..................................................................................................... Saginaw–125• Output Pressure (max)....................................................................................... 1450 psi (9997 kPa)• Flow Rate (max) ................................................................................................ 3.5 gpm (13.2 l/m)• Type ....................................................................................................................... Vane/Belt Driven

WINCHManufacturer. .............................................................................................................................. WARNModel .......................................................................................................................................... W6000Type ................................................................................................................................... 24V ElectricCapacity ................................................................................................................... 6000 lb. (2728 Kg)Safety .............................................................. Thermal Cutoff Switch (Protects Against Overheating)Safety ........................................................................ Overload Switch (Protects Against Overloading)


Page 6

WINCH DATAMaximum Load ................................................................................ Standard ............................MetricFifth Layer ........................................................................................ 3,360 lb .......................... 1524 kgFourth Layer ..................................................................................... 3,789 lb .......................... 1715 kgThird Layer ....................................................................................... 4,310 lb .......................... 1955 kgSecond Layer .................................................................................... 5,020 lb .......................... 2277 kgFirst layer .......................................................................................... 6,000 lb .......................... 2722 kg

VEHICLE DIMENSIONSLength Overall ...............................................................................................................180 in (457 cm)Height Overall .................................................................................................................69 in (175 cm)Height Minimum Reducible ............................................................................................55 in (140 cm)Width Overall ..................................................................................................................85 in (216 cm)Ground Clearance

Under Axle (Differential ................................................................................................16 in (41 cm)Under Chassis ................................................................................................................24 in (61 cm)

VEHICLE CRUISING RANGECruising Range M998.................................................................................................. 300 mi (482 km)Cruising Range M998A1 ............................................................................................. 337 mi (542 km)

MAXIMUM VEHICLE OPERATING SPEEDSTransmission Range Selection Transfer Case Range Selection

"L" Low Range "H" High Range "H/L" High Lock Range"R" Reverse 11 mph 29 mph 29 mph

(18 Km/h) (47 Km/h) (47 Km/h)"D" Drive 27 mph 55 mph 55 mph

(43 Km/h) (88 Km/h) (88 Km/h)"2" Second 19 mph 48 mph 48 mph

(31 Km/h) (77 Km/h) (77 Km/h)"1" First 11 mph 29 mph 29 mph

(18 Km/h) (47 Km/h) (47 Km/h)

CURB WEIGHTM998......................................................................................................................... 5200 lb. (2361 Kg)M998 A1 ................................................................................................................... 5380 lb. (2443 Kg)

GROSS VEHICLE WEIGHT (GVW)M998......................................................................................................................... 7,700 lb (3496 kg)M998 A1 ................................................................................................................... 7,880 lb (3578 kg)


Page 7

DESCRIPTION AND OPERATIONOF MAJOR COMPONENTS

Engine

Transmission

Transfer Case

Differential

Geared Hub


Page 8

MAJOR ENGINE SUBSYSTEMS

There are six major subsystems that support the operation of the engine. They are:

1. Fuel2. Air3. Lubrication4. Cooling5. Electrical6. Exhaust

Subsystems will be discussed individually.

Lubrication

ElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalElectricalCooling

Exhaust

Air

Fuel


Page 9

MAJOR COMPONENTS OPERATION

A. Air Cleaner -Filters air before it enters intake manifold.B. Engine-Provides power for the vehicle.C. Transmission-Transmits engine power to transfer case at varying speeds.D. Fuel Tank-Stores fuel.E. Geared Hub-Transfers turning action of halfshafts to wheels for vehicle motion.F. Pintle Hook-Permits towing of vehicles or equipment.G. Rear Propeller Shaft-Transmits power from the transfer case to the rear differential.H. Transfer Case-Provides full-time four-wheel drive with three drive ranges.I. Front Propeller Shaft-Transmits power from the transfer case to the front differential.J. Master Cylinder and Hydro-Boost-Provides hydraulic pressure and power assist for vehicle

stopping power.K. Steering Gear-Converts hydraulic power to mechanical power at the pitman arm.L. Differential -Transfers turning action of the propeller shaft to the geared hubs through the half

shafts.M. Winch -Electrically powered to provide recovery capability.

B C D

L I G

M

A

F

E

HJK

Major Exterior Components.


Page 10

ENGINE OPERATION & EXTERNAL COMPONENTS

The water-cooled, naturally aspirated, 6.2 liter, V-8, diesel engine provides up to 150 horsepower at3600 rpm to power the vehicle. The engine is identical on all military M998/M998 A1 modelsexcept those equipped with a deep water fording kit , which adds a specially sealed dipstick, dipsticktube, and vented CDR valve.

The engine has a compression ratio of 21.3:1. The cylinder block, main bearings, pistons and wristpins, are heavy-duty design because of the high compression ratio required in the diesel engine toignite the fuel.

Engine Operation and External Components.


Page 11

FUEL FILTER DRAIN VALVE

The fuel filter drain valve is located on the left front body cowl, in front of the windshield washerreservoir. The fuel filter should be drained daily, or after use. The engine must be running to drainthe fuel filter because the drain valve is higher than the fuel filter.

Fuel FilterDrain Valve

Fuel Filter Drain Valve.

PRECOMBUSTION CHAMBER

Precombustion chambers are used to assist in igniting the fuel. Before cold-starting the engine, theglow plugs are activated to preheat the precombustion chambers for faster starting. The majority ofthe ignition (combustion) occurs in the precombustion chambers. A light on the instrument panel willindicate when the engine is ready for starting.

Injector Nozzles

Glow Plugs1550 to 1650°F

Ricardo Comet VPrecombustion Chamber

Precombustion Chamber.


Page 12

LOCATION OF THE FUEL LIFT PUMP

The fuel lift pump provides fuel to the fuel filter and fuel injection pump at 4-8 psi. It is mounted onthe right front side of the engine block.

Manufacturer: AC Sparkplug DivisionType: Mechanical/Diaphragm

Fuel Lift Pump

Location of Fuel Lift Pump.


Page 13

FUEL INJECTION PUMP

The Model DB2 diesel fuel injection pump is described as an opposed plunger, inlet metered,positive displacement, gear driven distributor type pump. Electrical components are 24 volt DC andconsists of:

1. Fuel shutoff solenoid.

2. Housing pressure cold advance solenoid.

The HPCA solenoid advances the injection pump timing approximately 3-5° during engine warm up.The solenoid is activated when engine temperature is below approximately 80-90°F and isdeactivated) when engine temperature exceeds approximately 80-90°F (25-32°C).

Fuel Injection Pump Location.


Page 14

FUEL INJECTORS

The Bosch fuel Injectors require a 30 mm socket for removal and replacement. The injector nozzlehas a copper washer used to seal the combustion chamber area. Washers must be replaced wheneverinjectors are removed. When installing injector nozzles, apply anti-seize compound on the threadarea to prevent injector nozzles from seizing in cylinder heads. When testing for a suspected faultyinjector, place a cloth around the fuel line fitting to catch leaking diesel fuel. Loosen the fuel linefitting at the injector nozzle, and note any change in engine RPM. RPM's should decrease. If not,replacement of the injector nozzle or further testing of the injector nozzle with a injector nozzle testeris required.

NoteTo clean leak-off ports of built up wax and dirt, turn a drill bit by hand into the port hole and retract.Any wax deposits will be removed in the drill bit grooves.

CautionThe fuel injector nozzles in the 6.2L diesel engine must have the following color rings or poorperformance/severe damage could occur to the engine:

1991 and above Green1990 and below White

HIGH PRESSURE INLET

LEAK-OFF PORT

SHIM

PRESSURESPRING

NEEDLEVALVE

HEAT SHIELDWAVE WASHER

PINTLE NOZZLE

INTERMEDIATEPLATE

PRESSURESPINDLE

NOZZLE NUT

COPPERSEALINGWASHER

INTERMEDIATEPLATE

LEAK-OFF PORT

COLORRING

Fuel Injectors.


Page 15

FUEL SYSTEM SCHEMATIC

Ignition of the fuel in a diesel engine occurs because of heat developed in the combustion chamberduring the compression stroke. Thus, Spark plugs or high voltage ignition is not necessary for adiesel engine.

A fuel lift pump is driven by a lobe on the camshaft through a pushrod. Fuel is pulled from the fueltank by this mechanical fuel pump which is located on the right side of the engine and is pumpedbetween 4 and 8 psi. Fuel from the fuel pump travels to the fuel/water separator, which is located onthe body bulkhead above the left/rear of the engine, and on to the fuel injection pump.

From the fuel injection pump, diesel fuel is metered to the eight fuel injectors. The fuel injectorsopen between 1500 to 1960 psi injection pump pressure and allow fuel to be sprayed into theprecombustion chamber of the cylinder.

The fuel tank is vented through a fuel tank one-way vent filter located behind the coolant surge tank.

Tank Vent& Filter

FUELTANK

Strainer

InletSuctionLine

FUELPUMP

FuelFilter/WaterSeparator

Drain

Fuel Return Line

ColdAdvanceSolenoid

Return Line(One From EachFuel Injector)

Fuel PumpPressureTransducer

LowPressureLine

FUEL SOLENOID

INJECTIONPUMP

FUEL INJECTOR(8 Total)

569D 54A

High Pressure Line(one to Each FuelInjector)

ForSTE/ICETesting

Fuel System Schematic.


Page 16

HOUSING PRESSURE COLD ADVANCE SOLENOID (HPCA)

The housing pressure cold advance solenoid (HPCA) provides additional advance during enginewarm-up. It consists of a solenoid assembly and ball check return connector, located in the injectionpump governor cover. The electrical signal, which controls the operation of the solenoid, is generatedby a sensing unit mounted at the rear of the right hand cylinder head. An inoperative H.P.C.A.solenoid may cause white smoke and excessive noise on cold start until the engine warms up.

With engine temperature below 80-90°F (26.7-32.2°C), start and idle engine. Disconnect the HPCAsolenoid connector. If system is operating properly, a decrease in engine noise and a drop in enginespeed (approximately 100 RPM) will be noticed. If this does not occur, the system should bediagnosed.

FUEL RETURNVALVE

COOLANT

GOVERNOR

H.P.C.A.SOLENOID

+24 VOLTCOLDADVANCESWITCH RIGHT

CYLINDERHEAD

FUELINJECTION

PUMP

FUELRETURN

Housing Pressure Cold Advance Operation.

The cold advance switch is located at the rear of theright hand cylinder head, adjacent to injector #8.When engine coolant temperature is below 80-90°F(26.7-32.2°C), the switch is closed, allowing anelectrical signal to be sent to the cold advancesolenoid which advances the pump timing. Theswitch opens when the coolant temperature reachesapproximately 120°F (48.9°C).


Page 17

AIR INDUCTION SYSTEM

The air filter canister and intake stack are located on the right side of the vehicle, forward of thewindshield.

NOTE

To test system, remove air line (1) from restriction gageat air cleaner housing. Create a vacuum on the rubbertubing and observe gage. The float should move to thered position.

The air restriction gage provides a quick and accurate method for determining the extent ofrestriction in the vehicles air filter. It is located on the left side of the instrument panel. Before thefloat reaches the red portion of the gage, the filter should be serviced. The gage has a reset button thatreturns the float to its normal position.

Air Induction System.


Page 18

AIR CLEANER SERVICING

The air filter assembly may be cleaned by two methods: (1) Washing the element using a milddetergent and allowing the element to dry. (2) Using compressed air to blow debris out of theelement.

A dust unloader (3), located at the bottom of the air cleaner housing, is also included when servicingthe air cleaner. Accumulations of trapped dust and/or debris may be purged by simply compressingthe rubber boot.

Air Filter Servicing.

1 2

DUSTUNLOADER

CLAMP

AIR CLEANERASSEMBLY

3


Page 19

AIR INTAKE MANIFOLD

The intake manifold is a spider air plenum type which allows it to be completely separated from thecoolant system. This permits removing the intake manifold without disturbing the coolant system.The manifold is free standing and does not see any oil splash or heat from the crankcase. There areno coolant passages in the manifold. The tube for connecting the (CDR), Crankcase DepressionRegulator valve is on the right bank and must be installed on the right side.

Air Intake Manifold.


Page 20

CRANKCASE VENTILATION SYSTEM

The 6.2L crankcase ventilation system (A) is designed to reduce engine oil leaks by reducingcrankcase pressure at idle. The system consists of a crankcase depression regulator (CDR) valve,located on the right valve cover.

The CDR valve (B) is used to regulate (meter) the flow of crankcase gases back into the engine. Thevalve is designed to limit vacuum in the crankcase as the gases are drawn from the left valve cover,through the valve, and into the intake manifold (air crossover).

NOTEThe CDR valve can be tested by connecting a manometer to the engine dipstick tube and the otherend vented to atmosphere.

BA

COVER

DIAPHRAGM BODY SPRING

OUTLET TUBE(GASES TO INTAKE

MANIFOLD)

INLET PORT(GASES FROMCRANKCASE)CRANKCASE

DEPRESSIONREGULATOR

VALVE

CRANKCASEVAPORS

INLET MANIFOLDRUNNERS

CRANKCASE VAPORSTO

INDUCTION SYSTEM

BLOW-BYLEAKAGEAT VALVES

AND PISTONS

Crankcase Ventilation System.


Page 21

EXHAUST SYSTEM

The HMMWV exhaust system channels exhaust gases from the exhaust out of the leftrear side of the vehicle where they exit. The system consists of:

A. Exhaust HeadersB. Crossover PipeC. MufflerD. Tailpipe

Exhaust components are constructed of all stainless steel for corrosion protection. The exhaustcrossover pipe is bolted to the exhaust headers. The muffler is a reverse-flow double-pass and ismounted between the frame rails. The tailpipe is routed in front of the left rear wheel and out to theside of the vehicle. An extension must be added to the tailpipe for deep water fording (60 inch)[152.4 centimeters].

A B

DC

Exhaust System Components.


Page 22

EXHAUST HEADERS

Shown here are left and right exhaust headers. They are straight-flow, no baffles, providing lessbackpressure.

Exhaust Headers

Exhaust Header Locations.


Page 23

ENGINE LUBRICATION SYSTEM

The lubricating system used in the HMMWV engine is a pressure feed type. A pump forces oilthrough the galleries to the bearing surfaces. The system is composed of:

A. LifterB. Push RodC. CDR ValveD. RockersE. Cam Shaft BushingF. Main BearingG. Oil Pump Pickup

H. Oil PumpI. Drain PlugJ. Oil FilterK. Main Oil GalleriesL. Cam ShaftM. Oil Sending Unit

The oil pump is mounted on the rear main bearing cap. Oil is picked up by a tube and pumped to theoil cooler. The oil cooler is mounted in front of the radiator. Oil flows through the cooler and on tothe oil filter. The filter, located on the left rear of the engine, is a cartridge type.

The oil pressure sending unit is located on the left rear of the cylinder block to sense oil pressure inthe left main oil gallery.

AB

C D

L

K

E

F

GH

J

M

I

Engine Lubrication System.


Page 24

ENGINE NORMAL OIL FLOW SCHEMATIC

The lubricating system of this engine is a pressure feed type which means that a pump forces oilthrough the galleries to the necessary parts. The pump is mounted on the bottom side of the rear mainbearing cap. Oil is picked up by the oil pickup tube and pumped through the oil pump. The oil pumpis driven by the engine camshaft by means of an intermediate shaft.

The oil is then pumped through an oil cooler which cools the oil and helps remove engine heat. Fromthe cooler the oil passes through a filter. This filter is a cartridge type and all oil going to the engineshould pass through this filter. The filter is called a full flow filter, because all engine oil normallyflows through it.

Normal average engine oil pressure at stable conditions is 40-50 PSI @ 2000 RPM. The engine oilfilter bypass valve opens at 16-19 PSI above normal high (50 PSI), when increased pump pressuretries to pump oil through a clogged filter. When the bypass valve opens, the oil bypasses the filterand the engine continues to receive lubrication.

The engine oil cooler also has a bypass valve. It works the same as the oil filter bypass valve andopens to allow an alternate route for the oil if the cooler should become clogged. The oil coolerbypass valve opens at 9-11 PSI above normal high (50 PSI).

From OilPump

Rocker ArmPush Rod

Cam Bearings

Cooler Bypass Valve

Filter Bypass Valve

Oil Filter

Main Bearing

Valve Lifter

OilCooler

ToOil

Pump

ToOil

Pump

ToOil

Pump

ToOil

Pump

ToOil

Pump

Plug

Alternate Oil Flow Route–Cooler

Alternate Oil Flow Route–Filter

Engine Oil Flow.


Page 25

OIL PUMP DRIVE

The oil pump drive assembly is equipped with a drive gear on the lower end, which meshes with thecamshaft gear in the engine. The drive gear powers the engine oil lubricating pump.

Oil Pump Drive.


Page 26

OIL PUMP

The oil pump is a pressure feed-gear type which means that the pump forces oil through the galleriesto the necessary parts. The pump is mounted to the bottom side of the number five main bearing cap.

Extending down from the pump and into the oil is a pick-up tube with a screen cover to filter outforeign material. Oil is picked up by this tube and pumped through the oil pump to the oil coolerwhich cools the oil and helps to remove engine heat.

Oil Pump Drive.


Page 27

ENGINE OIL DIPSTICK LEVEL CHECKING PROCEDURES

Engine oil is checked with engine off. Pull out dipstick and check for proper oil level. Level shouldbe at crosshatch marks between “FULL” and “ADD 1 QT”.

If oil level checks above “FULL” , it may be due to oil cooler drain back. If this happens, operateengine for one minute, shut down, wait one minute, and recheck oil level.

AD

D 1

QU

AR

TF

ULL

Engine Oil Dipstick Location.


Page 28

COOLING SYSTEM FUNCTION

A. Coolant Pump: The coolant pump is mounted at the front end of the engine between the blockand the radiator. The pump consists of a housing, with a coolant inlet and coolant outlet.Internally there is an impeller which rotates, forcing the coolant through the housing. The pumpis belt driven. The coolant pump discharge rate, (flow) is 70 G.P.M. (271 liters per minute) andthe average coolant capacity is 6.2 gallons (23.5 liters) with 3.2 gallons (12.4 liters) in the engine.

B. Surge (Overflow) Tank: The surge tank is the filling and expansion point for the cooling system.Check surge tank cold. Level should be at or above full cold check line.

CoolantPump

GasketAdapter Plate

Surge TankCoolant Crossover

Vent HoseRadiator

Vent Hose

Overflow

LowerRadiator

Hose

Bracket

Coolant Pump and Surge Tank Function.

A B


Page 29


A. Thermostat: The thermostat shuts off coolant return flow to the radiator until temperaturereaches 190°F (88°C). The thermostat starts to open at 190°F (88°C) and is fully open at 212°F(100°C). Coolant is then directed to the radiator through the radiator inlet hose.

B. Fan Shroud: The radiator fan shroud permits a greater concentration of air to be pulled throughthe radiator. The fan shroud must be adjusted properly to ensure maximum air flow is achievedand to prevent damage to the fan and shroud.

Thermostat and Fan shourd Function.


Page 30


A. Engine Temperature Sending Unit: The sending unit transmits an electrical signal to atemperature gage mounted on the vehicle instrument cluster. The sending unit is mounted in acooling passage on the left front side of the left cylinder head adjacent to injector #1.

B. Coolant Crossover Pipe: The Coolant Crossover Pipe collects coolant from the cylinder headsand channels it to the thermostat housing where it is redirected through the cooling system. It hasthreaded bosses for installing a glow plug controller and a fan clutch thermostatic switch.

Engine Temperature Sending Unitand

Coolant Crossover Pipe Location


Page 31


A. Fan: The fan pulls outside air through the radiator to remove heat from coolant and oils.A 10 blade, plastic fan is used on the 6.2 L engine.

B. Radiator: The radiator is mounted at a 45° angle for a lower front vehicle profile. The radiatoralso provides for mounting of the transmission and power steering oil coolers.

Fan and Radiator Location.


Page 32

FAN CLUTCH FUNCTION(NOT ON VEHICLES WITH DESERT KITS INSTALLED)

A. Fan Clutch Solenoid: The hydraulic control valve electrical solenoid opens and closes thecontrol valve stopping oil flow to the fan clutch.

B. Hydraulic Control Valve: The hydraulic control valve directs hydraulic fluid to provide requiredpressure to activate fan clutch as required by engine temperature. Hydraulic pressure is suppliedby the power steering pump.

C. Time Delay Module: The Time delay Module sends a delayed signal to the fan clutch solenoidfor delay of fan actuation to provide needed horsepower for engine acceleration and to providefor adequate cooling of the engine

Fan Clutch Function.


Page 33

FAN CLUTCH FUNCTION(NOT ON VEHICLES WITH DESERT KITS INSTALLED)

A. Fan Thermostatic Switch: The fan thermostatic switch sends a signal to activate the controlvalve system to operate the fan when engine temperature exceeds 230°F (108°C) and deactivatewhen engine temperature drops below 190°F (88°C).

B. Fan Clutch: The fan clutch is hydraulically activated by pressure from the hydraulic controlvalve to control operation of the fan. Hydraulic pressure is provided by the power steering pump.

Fan Thermostatic Switch Locationand Fan Clutch.


Page 34

GLOW PLUG OPERATION

When engine temperature is below 120°F (48°C) and the rotary switch is positioned to “RUN”, the“Wait-T0-Start” light illuminates for up to fifteen seconds, depending on engine temperature. Whenthe light goes out, the engine can then be started. After the engine is started, the glow plugs willcontinue to cycle to compensate for cold air entering the engine cylinder. When the cylinders canmaintain a temperature of 120°F (48°C) the glow plugs will stop cycling.

Glow plug system is cycling normal when there is an on pulse for approximately 5 second and an offpulse for approximately 15 seconds.

The glow plugs are 12 volt and must have between 1.5 and 2.5 ohms resistance when tested with anohm meter. Once energized, 24 volts DC, forces current through the glowplug to cause it to glow orbecome red hot (1550-1650°F).

To detect glow plug system cycling, watch the voltmeter. The gage needle will move to the left whenglow plugs are on, then return to normal position when glow plugs are off. A relay click should beheard from the protective control box as the system switches on and off. A multimeter may be usedon any glow plug wire to visually watch operation of the glow plug system.

If engine temperature is above 120°F (48°C), glow plugs are not required for engine starting.Each glow plug draws approximately 11.25 amperes. To test system connect AMP meter acrossbatteries. With glow plugs cycling, there should be approximately 90 ampere draw. A defective glowplug will reduce ampere draw approximately 11.25 amperes. (Example) With one defective glowplug, reading will be approximately 78.75 amperes. With two defective glow plugs, reading will beapproximately 67.5 amperes etc.

1550°-1650°F

Glow Plug Operation.


Page 35

GLOW PLUG CONTROLLER

The glow plug controller is mounted in the coolant crossover tube on the right side of the engine, it iscontrolled by the engine coolant temperature and protective control box. It cycles the glow plugs offand on. It can be tested with an ohm meter. The new larger solid state controller (identified by a greencolor) cannot be tested with an ohm meter.

Glow Plug Controller Location.


Page 36

GLOW PLUG SYSTEM LOCATION

The glowplug power relay (In the protective control box) applies battery power to the glow plugswhen the three glowplug controller thermal breakers (inside the controller) are closed. You can hearthe power relay clicking as the glowplugs cycle.

Glow Plug System Location.

Batteries

Glow PlugController

Glow Plugs Wait to StartLamp

ProtectiveControl Box


Page 37

TRANSMISSION THM 400/3L80

The GM 3L80 automatic transmission provides three forward speeds and reverse. It includes a three-element hydraulic torque converter and a compound planetary gear set. Three multiple-disc clutches,one sprag, one roller clutch, and two bands provide the friction elements required to obtain thedesired function of the compound planetary gear set. Three external adjustments are also provided:kick-down/detent switch, linkage trunion, and the mechanically-operated modulator valve.

The torque converter smoothly couples the engine to the planetary gears through oil, andhydraulically provides additional torque multiplication when required.

The modulator is located on the right hand side of the transmission. A mechanically-operatedmodulator is required since the diesel engine produces very little vacuum. The top end of the cableconnects to the modulator link, which is connected to the throttle shaft on the fuel injection pump. Atthe transmission end, the cable connects to the modulator and modulator plunger through a ball andramp design. The plunger works against the modulator valve to provide the transmission with theproper engine load shift signals.

At speeds below approximately 45 mph (72.4 Kph), a detent downshift can be obtained by fullydepressing the accelerator. When fully depressed, the detent valve train replaces the modulator as acontroller of shift points. A kick-down switch, mounted at the right hand side of the fuel injectionpump, energizes the detent solenoid, thereby downshifting the transmission.

PRESSURE TESTPLUG

DETENT SOLENOIDELECTRICALCONNECTOR

GOVERNORCOVER

MODULATOROIL

COOLERFITTINGS

GM 3L80 Automatic Transmission.


Page 38

MODULATOR

The modulator indicates engine load to the transmission through the modulator linkage connected tothe fuel injection pump. It increases line pressure with increasing engine load for proper shifting ofthe transmission.

If the modulator is not correctly adjusted or not working properly it can create a pressure differentialwithin the transmission and cause delayed shifting.

If the modulator linkage is improperly adjusted it can create high pressure readings when pressuretesting the transmission.

The modulator cable should be checked and adjusted if the transmission has early/late shifts, or if thevehicle lacks normal acceleration. Adjust modulator cable to obtain a maximum travel of 1-1/2"(3.18mm) of cable core movement between idle and wide open throttle positions.

1-1/2"

LOOSENNUT

ADJUST TO 1-1/2" (3.18cm)MAXIMUM TRAVEL

FROM IDLE TOWIDE OPEN

Modulator Linkage.


Page 39

TRANSMISSION DETENT SOLENOID

When the accelerator is fully depressed, the detent solenoid replaces the modulator as a controller ofshift points. The detent solenoid can be tested using a conventional multimeter without priorcomponent removal. The solenoid coil resistance should be 60-70 ohms.

SOLENOIDELECTRICALCONNECTOR

Transmission Detent SolenoidElectrical Connector Location.


Page 40

NEUTRAL SAFETY SWITCH OPERATION

Operation of the neutral safety switch can be checked by placing the transmission shift lever in alloperating ranges while attempting to start the vehicle in each range. If the vehicle starts in anyposition other than “NEUTRAL”, replacement of the neutral safety switch may be required oradjustment of the linkage.

NeutralSafetySwitch

Neutral Safety Switch Location.


Page 41

TRANSMISSION COOLING SYSTEM

Transmission/Transfer Case Cooling System: The transmission fluid is cooled by the top half ofthe split oil cooler. Fluid flows from the transmission outlet to the top half of the oil cooler, then tothe transfer case, where it returns to the transmission. The transmission fluid that passes through thetransfer case does not mix with the transfer case fluid, but flows through a separate oil (secondary)cooler located within the transfer case.

Located in the front housing of the transfer case is a finned aluminum oil cooler. Oil, lower intemperature flows from the transmission oil cooler through the finned aluminum transfer case oilcooler, then back through the transmission where the cycle is continually repeated. The finnedaluminum cooler provides a method for heat transfer from the much warmer transfer case oil to thecirculating transmission oil.

SecondaryOil Cooler

TransferCase

Transmission/Transfer CaseOil Cooler Lines

Engine OilCooler Lines

Engine andTransmission

Oil CoolerRadiator

TransmissionOil Cooler

TransmissionOil Pump

Transmission Cooling and Bypass System.


Page 42

M998/M998A1 TRANSFER CASENEW VENTURE GEAR, MODELS 218 AND 242The transfer case on the HMMWV is a New Venture, full time four wheel drive. The M998 uses themodel 218 transfer case with a 2.61:1 gear ratio. The M998A1 uses the model 242 transfer case witha 2.71:1 gear ratio. An oil cooler is located inside the transfer case. This oil cooler assists in coolingthe transfer case lubricant when the transfer case oil is hotter than the transmission oil. When thetransmission fluid is hotter than the transfer case lubricant, the oil cooler will then assist in coolingthe transmission fluid.

The transfer case has three manually selected drive ranges that provide constant 4-wheel drive and aneutral.

HIGH LOCK (H/L)—Used to correct continuous wheel slippage (icy roads).

HIGH (H)—Normal power requirements (hard surfaces).

LOW LOCK (L/L)—Extra power requirements (steep grades).

DrainPlug

FillPlug

ShiftIndicator

Transfer Case.


Page 43

M998/M998A1 TRANSFER CASENEW VENTURE GEAR OPERATION, MODELS 218 AND 242The transfer case provides three ranges of constant four wheel drive: high range, high lock range, andlow lock range, and a neutral position. High range provides differentiated torque output to the frontand/or rear differentials, with a gear ratio of 1:1. The high lock range provides undifferentiatedtorque output to the front and rear differentials, with a gear ratio of 1:1. The low lock range positionprovides undifferentiated torque output similar to high lock range, but with a greater gear reductionat 2.72:1.

CLUTCH SLEEVE (ENGAGED) SIDE GEAR

CLUTCH GEAR

DRIVENSPROCKET

TOREAR

DIFFERENTIAL

TOFRONT

DIFFERENTIAL

TOTRANSMISSION

INPUTSHAFT

DRIVESPROCKET

MAINSHAFT

TOFRONT

DIFFERENTIAL

DRIVENSPROCKET

DRIVECHAIN

DRIVESPROCKET

TO REARDIFFERENTIAL

REAR OUTPUTSHAFT

SIDE GEARCLUTCHSLEEVE

(DISENGAGED)

INPUTSHAFT

TOTRANSMISSION

MAINSHAFT

FRONTOUTPUT SHAFT

DIFFERENTIALPINNION(S)

MAINSHAFT CLUTCH SLEEVE (ENGAGED)

INPUTSHAFT

ANNULUS GEAR

DRIVENSPROCKET

TOREAR

DIFFERENTIAL

TOTRANSMISSION

TOFRONT

DIFFERENTIAL

HIGH LOCK (H/L)—Used tocorrect continuous wheelslippage (icy roads).

HIGH (H)—Normal powerrequirements (hard surfaces).

LOW LOCK (L/L)—Extrapower requirements (steepgrades).

Transfer Case Model 242.


Page 44

DIFFERENTIAL OPERATION

The differential is a gear system that divides torque between the axle half shafts and allows them torotate at different speeds when cornering. The differential is a (torque biasing), (torque sensing)differential. It resists spinout by transferring more torque to the drive wheel that has the mostresistance to spinout.

The differentials are enclosed in the axle housing assembly and mounted up between the frame railsto minimize drive line vibration, external damage, and to increase ground clearance.

The front and rear differentials are interchangeable and have a gear ratio of:M998 2.56:1M998A1 2.73:1

Differential Components.


Page 45

GEARED HUBS

The geared hub is a gearbox located at the wheel ends, and is the final drive component. The geared hubpermits attainment of up to 16 inches (40.6 cm) of ground clearance to prevent damage to front or rearaxles. This ground clearance, together with the same high clearance of the chassis, maximizes crosscountry mobility.

Geared hub assemblies also serve as the front and rear wheel spindles. Each of the assemblies areinterchangeable at any wheel as long as the steering arm and cover are not on the hub. Two steering armcovers are required: one used on the left front and right rear geared hub, and another used on the right frontand left rear geared hub.

Each geared hub includes a drive gear and a driven gear, and are lubricated with standard 80/90 gear oil. Agear reduction of 1.92:1 decreases the force necessary to turn or stop the wheel. Using a geared hub allowsfor smaller differentials, brake assemblies, and halfshafts, which result in a lighter drive train.

Adjustable steering stops are located on the front geared hubs to limit the turning radius of the vehicle.

The geared hub is joined to the control arms by the ball joints bolted to the outer end of each arm. Tie rodsconnect the geared hub and wheel to the steering on the front suspension and radius rods at the rear.

Steering Stop

Steering StopLock Nut

Geared Hub.


Page 46

VEHICLE MECHANICAL SUBSYSTEMS

Additional functional subsystems on the HMMWV are:

• Central Tire Inflation System (CTIS)• Winch• Vent System• Steering• Service /Parking Brake• Suspension• Wheel / Tire / Runflat

CTIS

Vent System

Winch

Steering

Service/Parking Brake

Wheel/Tire/RunflatSuspension

Propeller/Halfshafts


Page 47

CTIS (CENTRAL TIRE INFLATION SYSTEM)

HMMWVs equipped with CTIS allow inflation or deflation of all wheel/tire assemblies while thevehicle is being driven. Air flows from a compressor through an air line and drilled air passagethrough the geared hub spindle. From the spindle, air flows through a quick disconnect fitting to thetire. An air seal in the geared hub control arm cover seals the spindle extension and prevents air fromentering the internal parts of the geared hub. This seal is stationary, while the spindle and extensionrotate as the vehicle moves. As air pressure is built up in the CTI System, air travels through thespindle out to the quick disconnect valve and air line to the wheel and tire assembly. The air seal alsoprevents geared hub lubricant from entering the CTI system.

Radial Tire

Wheel

Low ProfileRunflat

with Beadlock

Halfshaft

Air Seal

FromCompressor

SpindleAir Passage

QuickDisconnect

Fitting

Geared HubVent

(CTIS) Central Tire Inflation System.


Page 48

STANDARD STEERING CONTROL SYSTEM OPERATION

A. HYDRAULIC CONTROL VALVE— Directs hydraulic fluid to provide required pressure toactuate and deactuate the fan clutch as required by engine temperature. Hydraulic pressure issupplied by the power steering pump.

B. HYDRO-BOOST—Converts hydraulic power from the steering pump to mechanical power tothe master cylinder, providing power assist during braking.

C. ACCESSORY DRIVE PULLEY BELTS— Transmits mechanical driving power from crank-shaft drive pulley to steering pump pulley which drives the steering pump.

D. POWER STEERING COOLER—Directs power steering fluid through a series of fins orbaffles so outside air can dissipate excess heat before the fluid is recirculated through the steeringsystem.

E. OIL RESERVOIR AND STEERING PUMP— Combined in one unit, the reservoir serves as anoil filling point and the pump supplies the oil under pressure throughout the steering system,brake system hydroboost and fan clutch hydraulic contol valve.

Manufacturer: Saginaw Steering GearModel 125Vane Type, Belt Driven

Rated Capacity: 2.6 gpm @ 1500 rpm

F. FAN CLUTCH— Hydraulically-actuated by pressure from the hydraulic control valve to controloperation of the fan. Hydraulic pressure is supplied by the power steering pump.

Oil under high pressure, up to 1350 psi is pumped from the hydraulic reservoir pump to the brake-hydro-booster. From the brake booster, oil is then pumped under high pressure to the steering gearassembly. Oil is returned under low pressure to the steering oil cooler where it is cooled and thenpumped to the hydraulic control valve and on to the hydraulic reservoir.

When the hydraulic control valve is opened, oil will flow under low pressure (30-165 psi) to the fanclutch, disengaging the fan clutch.

Oil is returned through a low pressure line from the brake hydro-boost to the hydraulic reservoir.

G. STEERING GEAR—Hydraulically multiplies steering effort from the steering wheel andtransfers this effort to the front wheels through the steering linkage.


Page 49

High Pressure 1350 psi

Low Pressure 30–165 psi

B

E

F

D

C

A

G

Standard Steering ControlSystem Hydraulics Repeat.


Page 50

OPTIONAL STEERING CONTROL SYSTEM OPERATION

Optional steering control is provided for high temperature climates where constant fan operation isdesirable.

A. HYDRO-BOOST—Converts hydraulic power from the steering pump to mechanical power tothe master cylinder, providing power assist during braking.

B. ACCESSORY DRIVE PULLEY BELTS— Transmits mechanical driving power from crank-shaft drive pulley to steering pump pulley which drives the steering pump.

C. POWER STEERING COOLER—Directs power steering fluid through a series of fins orbaffles so outside air can dissipate excess heat before the fluid is recirculated through the steeringsystem.

D. OIL RESERVOIR AND STEERING PUMP— Combined in one unit, the reservoir serves as anoil filling point and the pump supplies the oil under pressure throughout the steering system.

E. STEERING GEAR—Hydraulically multiplies steering effort from the steering wheel andtransfers this effort to the front wheels through the steering linkage.

This hydraulic system provides the same brake hydro-boost, power steering system and oil cooler asthe standard system, without a hydraulic control valve or fan clutch. Instead, a solid drive fan is usedto cool the engine.

High Pressure 1350 psi

Low Pressure 30–165 psi

A

D

B

C

E

Optional Steering Control System Hydraulics


Page 51

STEERING CONTROL SYSTEM OPERATION

Turning effort at the steering wheel is transmitted to the steering gear, where it is hydraulicallymultiplied and transferred to the front wheels through the steering linkage.

Steering is accomplished through a two-piece assembly; an upper steering column and anintermediate shaft. The two pieces are universally jointed, and the intermediate shaft is also splinedto the steering gear stub shaft, and secured with a bolt through the slip yoke. Two lubrication fittingsare provided at the intermediate shaft.

The steering linkage consists of two adjustable tie rod assemblies, center link, pitman arm, and idlerarm. All components are connected by spring-loaded nonadjustable ball studs. Only the idler arm,pitman arm, steering shaft and tie rod ends have lubrication fittings. Each tie rod assembly has leftand right hand threads which allow for toe adjustments. Outer tie rod ends attach to the steering arm,and are bolted to the geared hub.

Steering Column

Intermediate Steering Shaft

Steering Gear

Pitman Arm

Idler Arm

Steering Wheel

Tie Rod Assembly

Geared Hub

Center Link

Tie Rod End

Steering Control System Components.


Page 52

STEERING STOP CHECK AND ADJUSTMENT

A. Check steering stops by marking reference lines on floor as indicated in the Technical Manual.

B. To Adjust steering stops, turn adjusting capscrew (1) in or out.

Steering Stop Reference Line Checkand Steering Stop Adjustment.


Page 53

TOE IN/TOE OUT CHECK

• On the HMMWV, the front wheels have toe/in and the rear wheels have toe/out.

• A quick check of the system is to use a tape measure and string to determine if the adjustment iswithin specifications listed in the vehicle maintenance manual.

NOTEVehicle should be at curb weight, 5,200 lb. (2,359 kg) to ensure proper alinement.Vehicle normal operating weight is optional and can be used when the vehiclesaverage operation is at less than gross vehicle weight.• Curb weight–Weight of base vehicle with all required lubes, fuel and

coolant. No crew, B.I.I. canvas or tools.• Pay load–2,500 lbs. (1,134 kg) above curb weight. Includes crew, canvas,

tools B.I.I and cargo.• Gross vehicle weight is curb weight plus payload.

Toe In / Toe Out Check.


Page 54

TOE-IN/TOE-OUT ADJUSTMENT

• The Front Wheel Toe/In is corrected by turning the threaded sleeve on the tie rod end assembly.

• The Rear Wheel Toe-Out is corrected by turning the threaded sleeve on the radius rod.

Toe-In / Toe-Out Adjustment.


Page 55

ALIGNMENT FRONT/REAR

To adjust and correct caster/camber, it will be necessary to remove the upper control arms to add orsubtract shims. Shims are placed between the upper control arm bracket and frame.

The HMMWV allows for caster/camber adjustment at each wheel.

FRAME UPPER CONTROL ARMBRACKET

UPPER CONTROLARM

SHIM

Caster/Camber Ajdustment.


Page 56

VENT SYSTEM

All components on the HMMWV are ventedthrough the air cleaner.

Transmission, Transfer Case, Geared Hub and Differential Assembly Vent Locations.

GEARED HUBVENT LINE

TRANSFERCASE

VENTLINES

TRANSMISSION

VENTLINE

DIFFERENTIALASSEMBLY

TO AIRCLEANER


Page 57

VENT SYSTEM

A vent system is incorporated within the vehicle's chassis which allows for fording of water up to 30inches (76.2 cm). The purpose of the vent system is to allow air to escape during normal vehicleoperation. The following components are interconnected by vent lines: geared hubs, front/reardifferential assemblies, transfer case, transmission, and optional winch. A vent filter is located behindthe air cleaner housing, and is used to vent the fuel tank. When the vehicle is equipped with a deepwater fording kit, a fording valve and a vented power steering pump cap are installed.

GearedHub

FordingValve

Transmission TransferCase

GearedHub

Geared HubGeared HubFuel TankVent Filter

Central VentSystem

Fuel TankVent

RearDifferentialFront

Differential

Vent System Components.


Page 58

SINGLE PARKING BRAKE SYSTEM OPERATION–SERIAL #1 THROUGH 44824HMMWVs with a serial number between 1 and 44824 have a single parking brake system. Thesystem consists of a parking brake lever, cable, rotor, pads and caliper. The caliper is mounted on abracket which is bolted to a rear crossmember. The rotor is connected to the rear differential by thefour rear propeller shaft mounting bolts.

PARKING BRAKE PADS

ROTOR

Cable

CALIPER ASSEMBLY

Single Parking Brake Operation.


Page 59

SERVICE/PARKING BRAKE SYSTEM OPERATIONSERIAL #44825 AND ABOVEThe parking brake system is a mechanically-actuated system that provides a means of keeping thevehicle still once it stops. It also assists in emergency stopping if there is a complete service brakesystem failure. Major components of the parking brake system are:

A. REAR BRAKE ROTORS— Attached to output flanges on rear differentials, rotors preventoutput flanges from turning when the parking brake is applied.

B. BRAKE PADS—Apply friction to rotors when the hand lever is applied.

C. REAR BRAKE CALIPERS— Force brake pads against rotors when the hand lever is applied.

D. PARKING BRAKE CABLES— Connect parking brake hand lever to equalizer bar.

E. EQUALIZER BAR— Evenly distributes braking pressure to the rear brake rotors.

F. PARKING BRAKE ROD— Connects parking brake hand lever to equalizer bar.

G. PARKING BRAKE HAND LEVER— Permits operator to engage the parking brake,

H. PARKING BRAKE HAND LEVER ADJUSTING CAP— Permits operator to make minortension adjustment of the parking brake.

F E DGH

C

B

A

Service/Parking Brake System.


Page 60

SERVICE BRAKE SYSTEMThe Braking system is an inboard four wheel front-rear hydraulically split disc system. The brakesare boosted by hydraulic pressure supplied by the vehicle's power steering system. This system alsoincludes an automatic adjusting parking brake mechanism which is part of the rear caliperassemblies.The service brakes consist of a brake pedal, push rod , hydro-boost, master cylinder, proportioningvalve, calipers, rotors, lines, mounting brackets, and fittings.

FRONT BRAKEROTOR

REAR BRAKEROTOR

PROPORTIONINGVALVE

MASTERCYLINDER

BRAKELINE

BRAKELINE

FRONTBRAKE

CALIPER

HYDRO-BOOST

SERVICE/PARKINGBRAKE CALIPER


Page 61

BRAKE MASTER CYLINDER AND HYDRO-BOOST SYSTEMThe service brake systme is identical for all HMMWV models. It is an inboard-mounted, four-wheel,disc brake, hydraulically-assisted systme. Major components of the service braking system are:

A. HYDRO-BOOST—Converts hydraulicpower from the steering pump to mechanical power tohte master cylinder, providing power assist during braking.

B. MASTER CYLINDER/RESERVOIR —Srores brake fluid, and converts mechnaical peddalpressure to hydraulic pressure.

C. PROPORTIONING VALVE —The proportioning valve section provides balanced front- torear braking action. The pressure differential vavle activates the brake warning lamp in case ofta brake systme failure, or brake fluid loss in either the front or rear hydraulic systmes.

D. ACCUMULATOR —Stores hydraulic pressure for additional power-asssited braking in theevent of a loss of pressure in the steering systme.

E. BRAKE-PEDAL —Provides operator control for stipping the vehicle.

F. BRAKE LINKAGE —Directs brake pedal pressure to the hydro-boost.

G. BRAKE WARNING SWITCH — This switch activates the brake light on the dash in case of abrake systme failure or brake fluid loss in either the fron or rear bydraulic systmes.

A

B

CD

E

F

G

Service Brake System Operation


Page 62

STOP LIGHT BRAKE SWITCH

The stop light switch is located above the brake pedal. To ensure correct adjustment of the stop lightswitch, the engine should be running, hand brake applied and wheels chocked. With the enginerunning, sufficient hydro-boost pressure is applied to the master cylinder, requiring less brake pedalapplication, and providing a more precise actuation of the brake light circuit.

STOP LIGHTSWITCH

Stop Light Switch.


Page 63

BRAKE PRESSURE WARNING SWITCH OPERATION

A brake pressure warning switch, mounted next to the master cylinder, is activated if either front orrear hydraulic systems fail. Under normal conditions, pressure is equal on both sides of the switchvalve. This will cause the switch valve to stay in a "centered" position. In this position, the groundcontact of the sending switch cannot touch ground. When the brakes are applied and a hydraulicpressure unbalance occurs, the side that has good pressure will push the switch valve over toward theside with the pressure loss. When this happens, the switch pin is forced up into the sending switch bythe ramp on the valve. This causes an electrical circuit to be made to ground, and the brake warninglight is turned ON. The light will stay ON as long as the unbalanced condition remains. When repairsare made, the valve is returned to its normal position by bleeding the brake system.

Brake Pressure Warning Switch.


Page 64

BRAKE FLUID

Dot 5 silicone brake fluid is used within the Hydraulic brake system. It can be distinguished fromconventional brake fluid by its color. Dot 3 and Dot 4 brake fluids are clear to amber in color, whileDot 5 contains a purple dye.

Silicone's most notable attribute is that it doesn't attract or absorb water. In fact, it repels water. Sinceit doesn't absorb water, moisture can't spread throughout the brake system to corrode metalcomponents. The properties virtually eliminates internal corrosion and fluid boil.

Silicone is chemically inert, non-toxic and will not damage paint like conventional brake fluid. It hasa higher boiling point than poly-glycol based fluids.

Adding Dot 3 or Dot 4 polyglycol brake fluid to Dot 5 silicone brake fluid is not recommended. Thetwo different fluids will remain separated like vinegar and oil.

MASTERCYLINDER

PROPORTIONINGVALVE

HYDRO-BOOST

Dot 5 Silicone Brake Fluid.


Page 65

SUSPENSION SYSTEM OPERATION

A. BALL JOINTS— Connects geared hub to control arms, and allows change of angle betweengeared hub and control arms during suspension movement.

B. UPPER CONTROL ARM— Connects geared hub to frame rail.

C. STABILIZER BAR (front only)—Prevents vehicle sway when cornering.

D. GEARED HUB—Serves as a mounting point for wheel and tire assembly and provides a 1.92:1gear reduction to increase torque to wheel and tire assembly.

E. LOWER CONTROL ARM— Connects geared hub to frame rail.

F. SHOCK ABSORBER—Dampens suspension movement and limits amount of suspension travel.

G. COIL SPRING—Supports weight of the vehicle and allows suspension travel to vary dependingon terrain and vehicle loading.

Suspension System Operation


Page 66

STABILIZER BAR OPERATION

The stabilizer bar (front only) prevents vehicle sway during cornering, and connects to the lowercontrol arms through bar links, and to the frame by stabilizer bar bushings.

Stabilizer Bar.

STUD

BAR LINK

STABILIZER BAR

FRAME BRACKET

CLAMP

BUSHING


Page 67

BALL JOINT INSPECTION

Front or rear lower ball joints may be inspected by raising the front or rear wheels approximately 2inches (5 cm) off the ground. With lower control arms supported, insert a prybar between the lowercontrol arm and geared hub. Push down on the prybar to try and move the hub. Measure anymovement in the hub assembly. If movement is more than 1/8 inch (0.3175 cm), replace the lowerball joint(s).

PRYBAR

MARK HEREAND

MEASURE MOVEMENN

RULERLOWER

“A” ARM

Lower Ball Joint Inspection.


Page 68

WHEEL AND TIRE COMPONENTS

The outer rim half is designed with two bolt patterns and accommodates a valve bore with an o-ring,locknut, and an insert for tire inflation. The locknuts which hold the two rim halves together arelocated around the outside periphery of the rim. The inner group of lugnuts fasten the wheel to thegeared hub spindle.

The wheel assembly, which includes a runflat device, allows the vehicle to be driven underemergency conditions with one or more flat tires. This does away with the immediate need for aspare tire and increases the vehicle mobility with flat tires.

In the event of a puncture or pressure loss in one of the tires, the operator can rely on the runflatdevices within each tire. The runflat insert enables the vehicle to travel 30 miles (48 Km) at 30 mph(48 Kph) with no air pressure in the tire. In the event that only the two rear tires are flat, Themaximum speed of the vehicle is 20 mph (32 Km). This reduced speed is necessary for vehiclecontrol. Two flat tires in the rear may cause the vehicle to sway from side to side at speeds above 20mph (32 Kph).

O-RING

LOCKNUT

OUTER RIM

BEADSPACER

TIRE

"0" RING

INNER RIM

BALANCE WEIGHT

VALVECOREINSERT

VALVEBORE

LOCKNUT

Wheel and Tire Components.


Page 69

RUNFLAT SYSTEM (BIAS DESIGN)

The runflat was designed to be used only during a life threatening, emergency situation. The tire willusually be damaged and require replacement after use.

Two 11 ounce grease packs are taped to the magnesium runflat, 180° apart to reduce friction whenoperating on a flat tire.

Bias tire size: 36" x 12.50" x 16.5".

Bias Tire With Runflat.


Page 70

RUNFLAT SYSTEM (RADIAL DESIGN)

The runflat was designed to be used only during a life threatening, emergency situation. The tire willusually be damaged and require replacement after use.

Two 11 ounce grease packs are taped to the hard rubber runflat, 180° apart to reduce friction whenoperating on a flat tire.

Radial tire size: 37" x 12.50R x 16.5".

Radial Tire With Runflat.


Page 71

RUNFLAT REMOVAL (RADIAL DESIGN)

Removal of the radial design one piece runflat assembly requires the use of a special tool called arunflat compressor tool.

TIRE RUNFLAT

RUNFLATCOMPRESSOR

RUNFLAT

RUNFLATCOMPRESSOR

STRAPHANDLE

ASSEMBLY

Runflat Compressor Tool.


Page 72

JACKING PROCEDURES

The vehicle may be raised using conventional hydraulic lifting devices. The lifting device padsshould be placed under one of the jack stand support points, lower control arms, under the front andrear suspension crossmembers or front and rear bumpers. If jacking under one of the suspensioncrossmembers, place a block of wood between the jack and the crossmember. When using a floorjack, lower the vehicle onto suitable jack stands until weight of vehicle is properly supported.

JACKSTAND

SUPPORTPOINT

JACKSTAND

SUPPORTPOINT

JACKSTAND

SUPPORTPOINT

JACKSTAND

SUPPORTPOINT

CROSSMEMBER

JACK

4 x 4 BLOCKOF WOOD

Jacking/Lifting Locations.


Page 73

WINCH 6,000 lb. (2721 Kg)

The vehicle's 24 volt electrical system is used to power the winch motor. The winch circuity consistsof an electronic current limiter switch which prevents winch overload, and is located in the solenoidpack. A thermal cutoff switch is also used to prevent the winch motor from overheating duringoperation. The cutoff switch is mounted within the motor. The winch is a 6,000 lb (2721 kg) capacity.

6,000 lb Winch.


Page 74

PROPELLER SHAFTS

The HMMWV uses two tubular propeller shafts to transmit torque from the transfer case to the frontand rear axle assemblies. Universal joints, located at either end of the front and rear propellershafts, permit in-line driving power between the transfer case and differentials even though they aremounted at different angles.

Front and Rear Propeller Shafts.


Page 75

HALFSHAFTS

The HMMWV utilizes 3 different length axle drive shafts (halfshafts) to accommodate the independentsuspension system. The left front and right front halfshafts are unequal in length due to the off centeredpositioning of the front differential. The rear halfshafts are equal in length, but not the same length aseither of the front halfshafts.• Short shaft Left front.• Intermediate shaft Both rear.• Long shaft Right front

The purpose of the halfshafts is to transfer torque to the wheels from the differential through thegeared hub. Each unit is basically a one-piece assembly with boots on both the inboard (differential)and outboard (geared hub) ends.

The outer boot encloses a constant velocity joint which transmits torque through various steeringangles to the geared hub. The outer (splined) constant velocity joint end of the shaft assembly is heldin place by the axle shaft retaining bolt located opposite the pipe plug in the geared hub. The innerhousing is bolted to the differential output flange.

NOTE

Removal of either the front or rear halfshaft requires that the respective tire be removedfor accessing the access plug and retaining capscrew.

Halfshaft.


Page 76

ELECTRICAL SYSTEM

The electrical system for the 6.2L diesel engine is a 24 volt system capable of submerged operationduring fording.

The engine electrical system consists of:• Starting system• Generating system• Windshield washer/wiper system• Battery system• Lighting system• Winch• STE/ICE-R

Lighting SystemWindshield

Washer/wiperSystem

Starting System Generating System

Battery System

Winch

STE/ICE-R


Page 77

STARTING SYSTEM OPERATION

The starting system is identical for all military vehicles, and consists of the following componentsand circuits:

A. ROTARY SWITCH— When in “START” position, provides battery power to the starter solenoidand to the neutral start switch through circuit 14.

B. NEUTRAL START SWITCH— When transmission shift lever is in “N” (neutral) position, thisswitch closes a relay in the protective control box through circuit 14 allowing battery power toreach the starter solenoid.

C. PROTECTIVE CONTROL BOX— Locks out the starter circuit, which prevents the starterfrom reengaging while the engine is running.

D. STARTER SOLENOID—A magnetic relay that transmits 24-volt battery power to the startermotor.

E. STARTER MOTOR— Cranks the engine for starting, and is supplied 24-volt battery powerthrough circuit 6A.

F. BATTERIES— Two 12-volt batteries connected in series supply 24-volts to the starter systemthrough circuit 6A.

G. GLOW PLUG(S)—Assists in cold starts and is connected through circuit #575 at the protectivecontrol box.

H. GLOW PLUG CONTROLLER —Cycles the flow plugs on and off during sold starts. It isconnected to the protective control box through circuit #573A.

G

A B C

D

E

14 14

74A

6A

575A

573A

H

F

BODYCONNECTOR

ENGINECONNECTOR

Starting System Operation.


Page 78

GENERATING SYSTEM OPERATION—60/100 AMPERE

The 60/100 ampere generating systems maintains battery charge and provides electrical power tooperate vehicle circuits. Major components of the generating systems are:

A. BATTERY GAGE —Indicates electrical system voltage. It is connected to the electrical systemthrough circuit 567.

B. ALTERNATOR (100 ampere Prestolite/Niehoff)—Rated at 28 volts, 100 amperes, withexternal regulator. The alternator assists and recharges the batteries during operation.

C. ALTERNATOR (60 amperes)—Rated at 28 volts, 60 amperes, with internal regulator, thealternator assists and recharges the batteries during operation.It is the only alternator with anadjustable regulator.

D. CIRCUIT 3 —Provides a ground circuit to alternator.

E. CIRCUIT 5 —Conducts alternator output to charge the batteries and maintain vehicle voltage.

F. CIRCUIT 568—Senses vehicle voltage activating the field current in the alternator to generatecurrent.

G. PROTECTIVE CONTROL BOX —Protects the vehicle electrical system in the event batterypolarity is reversed.

567 27

35568

569 A. Battery GageB. Alternator 100 AmperesC. Alternator 60 AmperesD. Circuit 3E. Circuit 5D. Circuit 568G. Protective Control Box

A

B

D

E

F

G

C

60/100 Ampere Generating System.


Page 79

GENERATING SYSTEM OPERATION—200 AMPERE

The 200 ampere generating system maintains battery charge and provides electrical power to operatevehicle circuits. Major components of the generating system are:

A. BATTERY GAGE —Indicates electrical system voltage. It is connected to the electrical systemthrough circuit 567.

B. ALTERNATOR (200 ampere)—Is rated at 28 volts, 200 amperes, with external regulator. Thealternator assists and recharges the vehicle batteries during operation.

C. CIRCUIT 568/CIRCUIT 5 —Senses vehicle voltage, and activates the field current in thealternator to generate current.

D. PROTECTIVE CONTROL BOX —Protects the vehicle electrical system in the event batterypolarity is reversed.

E. CIRCUIT 2—Sends AC signal, indicating alternator shaft rpm, to frequency switch in theprotective control box to prevent operation of the starter solenoid when the engine is running.

F. BATTERIES—Two 12-volt batteries are connected in a series to provide 24 volts to start thevehicle and assist alternator during operation.

G. POSITIVE CABLE —Transmits alternator output to maintain battery charge. A fuse at thealternator power stud will prevent damage to the alternator if battery polarity is reversed.

H. CIRCUIT 3 —Connects to negative stud on alternator with engine ground strap to provide aground circuit to alternator.

568

27

5695

3

567C

H

E

FG

B

A

2D

Generating System Operation.


Page 80

BATTERY SYSTEM OPERATION

The battery system is identical for all military M998 and M998A1 vehicles and consists of the followingcircuits and components:

A. CIRCUIT 6A —Connects the batteries to the starter and to the protective control box through circuit 74A.

B. BATTERIES—Two batteries are connected to provide 24 volts D.C. for the electrical starting system.

Type—Lead acid dry charge, 6TN.

Capacity at 20 hour rate—100 amp. hour

C. SLAVE RECEPTACLE —Links an external power source directly to the slaved vehicle’s batteries toassist in cranking the engine when the vehicle’s batteries are not sufficiently charged.

D. SHUNT—Used when measuring current draw from the batteries utilizing STE/ICE (grounded tochassis).

E. PROTECTIVE CONTROL BOX —Protects the vehicle electrical system in the event the batterysystem polarity is reversed.

F. ROTARY SWITCH —When in “START” position, actuates starter solenoid through circuit 11A and 74A.When in “RUN” position, closes circuit 29A to activate instrument cluster gages through circuit 27.

G. CIRCUIT 7A —Connects the battery system to the starter negative terminal and chassis ground.

H. STARTER SOLENOID—Actuates starter motor gear to crank vehicle engine.

6A

50A

50A

49A

74A

11A

HA

C

D

E

F

G7A

B

Battery System Operation.


Page 81

WINDSHIELD WIPER/WASHER SYSTEM OPERATION

A. WINDSHIELD WIPER MOTOR— Wipers are powered by a 2-speed electric motor. When theknob is turned to “LOW” or “HIGH” position , circuit 27 carries battery power to wiper motor toactivate windshield wipers.

B. CIRCUIT 57—Provides a ground circuit for the wiper motor.

C. WINDSHIELD WASHER MOTOR— When the wiper motor knob is pushed, the washer motoris activated through circuit 71 to spray water onto the windshield.

Reservoir Capacity—1 gallon (3 quarts usable)— 3.875 liter (2.8 liters usable)

A B

57

71

C

Windshield Wiper/Washer System.


Page 82

Blackout Drive Lamp

WhiteLight

Front Blackout Marker Lamps

WhiteLights

Rear Blackout Lamps

12 34

RedLamps

WhiteLamp

VEHICLE LIGHTS LOCATION AND FUNCTION

The purpose of rear blackout markers is for use in night convoy operation. The blackout marker lightsare commonly referred to as “Cat Eyes”. When following another HMMWV in convoy and you cansee 4 each red blackout markers, you are driving to close to the vehicle in front of you. If you do notsee any cat eyes, you are too far away from the vehicle in front of you. If you see 1 cat eye blackoutmarker on each side, you are still too far from the vehicle in front of you. If you can see 2 red cateyes on each side of the vehicle you are about the right distance from the vehicle in front of you.

Purpose of the front black out markers:Night Illumination for blackout conditions.

Front Blackout Marker2 white lights–too far away1 white light–correct distance

Rear Blackout Markers:4 red lights on each side–too close2 red lights on each side–Correct distance1 red light on each side–too far awayNo lights–You’re in trouble

Blackout Drive Lamp

Turn SignalBlackout MarkerParking Lamp

Headlamp

Brake LampTurn Signal

Blackout Tail LampBlackout Stop Lamp

Front View Rear View

Vehicle Lighting System.


Page 83

WINCH OPERATION

A. WINCH CONTROL ASSEMBLY— The control assembly consists of four heavy duty solenoids,a thermo switch, (located in the motor armature brush hoolder) and a Electronic Current Limiter(ECL).

B. MOTOR— The winch is powered by a 24 VDC Warn motor.

GREEN

RED LEADOF E.C.L.

TO POSITIVE (+)BATTERY

TERMINALWHITE LEAD OF

REMOTE SWITCH

BROWN LEADOF E.C.L. GREEN LEAD

OF E.C.L.

TO MOTOR THERMALPROTECTION SWITCH

BLACK TOMOTOR

ARMATURE

BLACK TOMOTOR

FIELD NO.1

RED TO MOTORFIELD NO.2

BLACK

E.C.L.

Winch Solenoid Pack.

B.

A.


Page 84

STE/ICE-R

Description and Operation—STE/ICE-R is a testing system that performs test and measurementson internal combustion engines. STE/ICE-R measures standard voltage, current, resistance, pressure,temperature and speed. Special tests, such as compression balance tests and starter systemevaluations, are performed by STE/ICE-R. Standard equipment function including vacuum pressuregage, compression gage, low-current tester and multimeter are features of the STE/ICE-R set. STE/ICE-R is portable and operates on either 12 or 24 volt vehicle batteries or equivalent power source.The STE/ICE-R system consists of a vehicle test meter (VTM), a transducer kit (TK), four electricalcables, a transit case and technical publications.

Power/DCA Connector J1. Connector J1 connects the VTM to either a vehicle diagnostic connectorusing the DCA cable or to the vehicle batteries using the power cable. Operating power and signalsfrom the installed transducers are supplied to the VTM through the DCA cable.

The VTM produces a method for the technician to test vehicle electrical and mechanical components.Readings are either pass/fail indications or digital displays in units familiar to the technician (psi,rpm, volts, ohms, amps, etc.).

3 2

TEST

PUSH ON

PULL OFF

TEST SELECT

J4VOLTS/OHMS

J1 DCA/PWR J2 TK J3 TK

TRANSDUCERCABLE CONNECTORS

READOUTDISPLAYTEST PROBE

CABLECONNECTOR

FLIPCARDS

TESTSELECT

SWITCHES

TESTBUTTON

DIAGNOSTICCONNECTOR/PWR

ASSEMBLY W1

DCA/POWERCONNECTOR

J1

POWERON/OFF

STE/ICE-R Testing System.

M998A1 Intro/Veh Sys Text - Steel Soldiers

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