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山推 BYD4208 变速箱维修手册
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Bs428 Transmission Workshop Mannual 20156

Feb 20, 2016

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George Jhonson

Bs428 Transmission Workshop Mannual 20156
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Page 1: Bs428 Transmission Workshop Mannual 20156

山推 BYD4208 变速箱维修手册

Page 2: Bs428 Transmission Workshop Mannual 20156
Page 3: Bs428 Transmission Workshop Mannual 20156

BS428 Transmission Service Manual

Foreword

This service manual mainly covers the removal and refitting process, service technology and

standard requirements for BS428 transmission (also applies to BYD4208 series transmission), so as

to help service personnel understand the method of removing and refitting it and to lay a solid

technical foundation for them concerning proper fault diagnosis and troubleshooting.

This service manual mainly includes the following:

Chapter 1 Introduction

This chapter mainly describes precautions for servicing transmission, explains the meaning of each

symbol which are included in the following text and specifies the tightening torque for plain bolts.

Chapter 2 Transmission system

This chapter mainly describes the gearshift principle of transmission, the transmission line of each

gear, and the operation and maintenance of oil supply line and transmission.

Chapter 3 Removal of transmission

This chapter describes how to remove each part properly and the relevant precautions in the

process.

Chapter 4 Refitting of transmission

This chapter describes how to refit each part properly and the relevant precautions in the process.

Chapter 5 Service tools for transmission

This chapter describes special tools required in the process of servicing transmission.

Chapter 6 Fault diagnosis and troubleshooting

This chapter describes common faults and troubleshooting of the transmission.

Note

The specifications of parts covered by this Manual may be subject to modification due to the

improvement of this product, and no further notice will be given upon such modification, so

please contact SDLG for the latest data.

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BS428 Transmission Service Manual

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Contents

1 Introduction ................................................................................................................ 1

1.1 Safety precautions ............................................................................................. 1

1.2 Description of signs ........................................................................................... 2

1.3 Tightening torque table for plain bolts .............................................................. 3

2 Transmission system .................................................................................................. 5

2.1 Description of transmission ............................................................................... 5

2.2 Basic parameters of transmission & torque converter assembly ...................... 6

2.3 Structure and principle of transmission ............................................................. 6

2.3.1 Structure of transmission ........................................................................... 6

2.3.2 Shifting principle of transmission .............................................................. 7

2.3.3 Gear transmission lines .............................................................................. 8

2.3.4 Structure and principle of shifting clutch ................................................ 10

2.3.5 Structure and principle of automatic emptying valve (oil drain valve) ... 11

2.4 Oil supply system ............................................................................................ 13

2.4.1 Structure and working principle of transmission & torque converter oil

supply system .................................................................................................... 13

2.4.2 Introduction to oil supply system main components ............................... 14

2.5 Transmission Operation and Maintenance ...................................................... 18

2.5.1 Installation and Application Notices for Transmission ........................... 18

2.5.2 Maintenance of Transmission .................................................................. 18

3 Removal of Transmission ......................................................................................... 20

3.1 Removal of assembly components .................................................................. 20

3.1.1 Removal of oil filler pipe and filter ......................................................... 20

3.1.2 Removal of parking brake assembly ....................................................... 21

3.1.3 Removal of transmission control valve ................................................... 22

3.1.4 Removal of breather and cover plate ....................................................... 23

3.1.5 Removal of input flange .......................................................................... 23

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3.1.6 Removal of oil sump ................................................................................ 23

3.1.7 Removal of high/low gearshift fork mechanism ..................................... 24

3.1.8 Removal of output shaft ........................................................................... 24

3.1.9 Removal of three sets of clutch gear shafts ............................................. 26

3.2 Removal of assembly ...................................................................................... 28

3.2.1 Removal of transmission control valve ................................................... 28

3.2.2 Removal of three sets of clutch gear shaft assemblies ............................ 30

4 Refitting of Transmission ......................................................................................... 34

4.1 Refitting of assembly ....................................................................................... 34

4.1.1 Refitting of clutch shaft assembly ........................................................... 34

4.2 Refitting of assembly components .................................................................. 38

4.2.1 Assembly of three sets of gear shafts ....................................................... 38

4.2.2 Refitting of input flange and rear end cover ............................................ 40

4.2.3 Assembly of countershaft and reverse gear shaft rear end cover ............ 41

4.2.4 Assembly of output shaft ......................................................................... 42

4.2.5 Assembly of high/low gearshift fork mechanism .................................... 42

4.2.6 Assembly of oil sump .............................................................................. 43

4.2.7 Assembly of transmission control valve .................................................. 43

4.2.8 Assembly of breather and cover plate ...................................................... 44

4.2.9 Assembly of parking brake assembly ...................................................... 44

4.2.10 Assembly of oil filler pipe and filter ...................................................... 45

5 Service Tools for Transmission ................................................................................ 46

6 Common Fault Diagnosis and Troubleshooting ....................................................... 47

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1 Introduction

1.1 Safety precautions

Important safety notice

Service and maintenance is essential to the safe operation of vehicle. This Manual mainly

states the related techniques on how to remove and refit the transmission assembly properly.

To prevent relevant personnel from being hurt, this Manual takes as safety sign. With

regard to precautions attached with this sign, it is required to do operation carefully. In case

of potential hazard, first take into account the safety of yourself, and meanwhile take

necessary protective measures.

Safety notice

In the process of refitting and removal, improper operation technique will lead to part damage,

service life reduction and deterioration in operating performance, and in addition, it may cause

unsafe factors. Therefore, please read related content in this manual carefully before refitting and

removing any part.

1. The parameters, figures and content covered by this manual apply to product of standard

configuration. As regard to variant, please consult our coMPany or relevant data.

2. In repair workshop, a separate or special area shall be set for placing removed parts,

corresponding tools and parts shall be placed at appropriate area, and the operation area shall be

kept clean and free of oil dirt and other contaminant. Do not smoke at any place other than the

specified area. Never smoke during operation, and it is required to have fire extinguishing device.

3. When welding operation is necessary, it shall be done by a trained and experienced welding

worker. During welding, it is required to wear and use appropriate protective equipment such as

welding gloves, baffle, goggles, work cap and overall.

4. Before removing transmission & torque converter assembly, make sure to clean the dirt from its

external surface so as to prevent parts from being contaminated during removal.

5. During operation, do wear safety shoes and safety helmet. Do not wear inappropriate work coat.

The work coat must be buttoned. When striking parts with a copper rod, safety goggles shall be

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worn.

6. Petrol, kerosene and water-based oil cleaner can be used to clean the removed parts.

7. To use a crane or other hoisting equipment, first check the slings for damage. It is required to use

hoisting equipment with sufficient lifting capacity. During lifting operation, do lift slowly at

appointed position so as to prevent parts from striking against each other. Do not work under the

lifted parts.

8. When two or more people are required to work simultaneously, they shall be in agreement with

the same operation procedure in advance to avoid accident due to out of step conditions.

9. Make sure to keep all tools properly and get familiar with their operating methods.

10. To align one hole with another, do not get your hand or finger into the holes. As regards to parts

requiring direct assembly with hand, always pay attention to the holding position and check it for

risk of crushing.

11. Make sure to perform inspection on the removed parts. The part of which the defect has already

affected the performance must be replaced.

12. After assembling all parts, no interference is allowed.

13. When assembling the oil seal and seal ring, if they have to pass key groove, screw hole and step,

then corresponding protective measures shall be taken so as to avoid damaging them.

14. In the process of refitting parts, the tools used shall match corresponding threaded fasteners so

as to prevent the fasteners from being damaged.

15. To tighten joint body and plug screw, do not use pneumatic wrench. Be sure to rotate them to

some extent with hand, and then tighten them with torque wrench of corresponding specification to

the required torque value.

16. When draining oil from transmission, be sure to unscrew the drain plug slowly so as to prevent

oil from spurting out.

1.2 Description of signs

To make this manual fully play its roles, the signs in Table 1-1 are used in respect of critical safety

and quality requirements.

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Table 1-1

Sign

Item Remarks

Safety

During operation, pay special attention to safety.

During operation, pay special attention to safety because of

inside pressure.

Note

During operation, pay special attention to technical

requirements so as to ensure operation quality.

Weight

Weight of component or device and removal & refitting modes.

Pay attention to the selection of sling and the postures during

operation.

Tightening

torque

Pay special attention to the tightening torque of component

during assembly.

Application Points requiring the application of adhesive and grease.

Oil and water Add a certain amount of oil, water and fuel.

Draining Position for draining oil or water, as well as draining amount.

1.3 Tightening torque table for plain bolts

Table 1-2

Strength

class

Yield

strength

(N/mm2)

Nominal diameter of bolt (mm)

6 8 10 12 14

Tightening torque (Nm)

8.8 640 9~12 22~30 45~59 78~104 124~165

10.9 900 13~16 30~36 65~78 110~130 180~210

12.9 1080 16~21 38~51 75~100 131~175 209~278

Strength

class

Yield

strength

(N/

Nominal diameter of bolt (mm)

16 18 20 22 24

Tightening torque (Nm)

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mm2)

8.8 640 193~257 264~354 376~502 521~683 651~868

10.9 900 280~330 380~450 540~650 740~880 940~1120

12.9 1080 326~434 448~597 635~847 864~1152 1098~1464

Strength

class

Yield

strength

(N/

mm2)

Nominal diameter of bolt (mm)

27 30 33 36 39

Tightening torque (Nm)

8.8 640 952~1269 1293~1723 1759~2345 2259~3012 2923~3898

10.9 900 1400~1650 1700~2000 2473~3298 2800~3350 4111~5481

12.9 1080 1606~2142 2181~2908 2968~3958 3812~5082 4933~6577

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2 Transmission system

2.1 Description of transmission

BS428 transmission is a fixed shaft, constant mesh and power gearshift transmission, which is

mainly used for LG933L and LG936L loader. In the transmission system of LG933L and LG936L,

the engine is directly connected to the torque converter via an elastic plate so as to realize output

power, and torque converter is connected via the propeller shaft to front input flange of the

transmission where speed change and torque increase happens such that the power can be

transmitted to front and rear drive axles via front and rear propeller shafts respectively.

BS428 transmission mainly consists of input shaft assembly, countershaft assembly, and reverse

gear shaft assembly, high-low gear sliding sleeve as well as its control mechanism and many pairs

of constant mesh gear, etc.

Fig. 2-1

1.Breather 2.Transmission control valve 3.Reverse gear shaft 4. Input shaft 5.Countershaft

6.Oil drain plug 7.High-low gearshift fork 8.Output shaft 9.Filter 10.Oil filler pipe

11.Parking brake

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2.2 Basic parameters of transmission & torque converter assembly

Table 2-1

Item Parameters/description

Torque

converter

Type Single-stage three-element turbine hydraulic

torque converter

Torque ratio 3.25

Oil pressure at torque converter inlet

(MPa) 0.5~0.6

Oil pressure at torque converter

outlet (MPa) 0.2~0.3

Transmission

Type Fixed-shaft power shift

Gears 4 gears in front and 2 in the rear

Transmission working pressure

(MPa) 1.1~1.5

2.3 Structure and principle of transmission

2.3.1 Structure of transmission

BS428 transmission includes three sets of normally opened clutches, which are closed by hydraulic

fluid, and they control the 1st gear, 2nd gear, 1st reverse gear respectively, or the 3rd gear, 4th gear

and 2nd reverse gear when the shift fork is set to a higher gear. The one installed on the input shaft

is the 1st gear clutch; the power from torque converter is transmitted to input shaft via a connecting

flange and the input shaft is the total input of transmission. The one installed on the countershaft is

the 2nd gear clutch, and the countershaft can transmit the power from the 1st gear and the reverse

gear to the output gear. The one installed on the reverse gear shaft is the reverse gear clutch which

can make the loader drive backwards when it is engaged.

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Fig. 2-2

1. Reverse gear shaft clutch 2. Input shaft clutch 3. Intermediate gear shaft clutch

2.3.2 Shifting principle of transmission

The transmission’s gearshift mechanism is a mechanically-operated one, with the gear controller of

BS428 transmission shown in Fig.2-3. This gear controller includes two gearshift levers: 1.

direction control handle (see Fig. on the left), which connects to the gearshift control valve stem on

the transmission via a flexible shaft; 2. high/low speed control handle (see Fig. on the right), which

connects to the shift fork on the transmission via a flexible shaft. The gear controller operates the

clutches of different gears by controlling the speed change valve. The working conditions of

clutches are shown in table 2-2.

Fig. 2-3 Gear selector

View from input terminal Input shaft

Reverse gear shaft

Countershaft

Output shaft

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Table 2-2 Working conditions of clutches

Ⅰ Ⅱ Ⅲ Shift fork

Ⅰ √

Ⅱ √

Ⅲ √

Ⅳ √

Ⅰ √

Ⅱ √

2.3.3 Gear transmission lines

The power of the hydraulic torque converter is transmitted to the transmission via the input shaft

flange installed on the part of the right end of the input shaft that extends outside the transmission

box. The input shaft assembly, reserve gear shaft assembly and immediate shaft assembly connects

with the transmission box in the same way. Both ends of them are supported on the transmission

box and big end cap by conical bearings. Adjust the clearance of conical bearing during assembly,

to avoid damage to the bearing. The gears on the output shaft assembly, reverse gear shaft assembly,

countershaft assembly and output shaft are constantly meshed with each other. There are three stop

positions (HI, N, LO) in the high-low gear sliding sleeve which is refitted on the output shaft. The

high gear position corresponds to a high speed; the low gear position corresponds to a low speed.

When the sliding sleeve stays at the neutral position, no power will be output by the transmission.

Caution: Never shift the high-low gear sliding sleeve before the transmission is in the

neutral gear after the loader is stationary, otherwise, impacting and crashing of the gears may

occur.

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1. 1st (3rd) gear transmission line

Fig. 2-4

3rd gear (when the shift fork is set to the right

high speed gear):

input→Z3→Z4→Z7→Z9→output

1st gear (when the shift fork is set to the left

low speed gear):

input→Z3→Z4→Z7→Z5→Z8→Output

2. 2nd (4th) gear transmission line

Fig. 2-5

4th gear (when the shift fork is set to the right

high speed gear): input→Z3→Z6→Z7→Z9→

output

2nd gear (when the shift fork is set to the left

low speed gear): input→Z3→Z6→Z5→Z8→

output

3. 1st (2nd) reverse gear transmission line

1nd reverse gear (when the fork is set to the left

low speed gear): input→Z3→Z1→Z2→Z7→

Z5→Z8→output

2nd reverse gear (when the fork is set to the

right high speed gear): input→Z3→Z1→Z2→

Z4→Z7→Z9→output

Reverse gear shaft

Input shaft

Countershaft

Output shaft

Reverse gear shaft

Input shaft

Countershaft

Output shaft

Reverse gear shaft

Input

shaft Countershaft

Output shaft

Input shaft

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Fig. 2-6

2.3.4 Structure and principle of shifting clutch

1. Structure

The housing and gear of the hydraulic clutch is fixed together with bolts, and the gear connects to

the external spline of the propeller shaft via the internal spline, all of which consist of the driving or

driven part of the clutch. The inner part of the clutch consists of piston, outer friction lining, inner

friction lining, oil seal ring, return spring, outer end cover, retaining ring, etc. The driving friction

lining of the clutch connects to the clutch housing via the external spline, and the driven friction

lining of the clutch connects to the external spline of the gear via the internal friction lining.

Another gear is supported on the propeller shaft by the bearing and can rotate with respect to the

propeller shaft.

The outer friction linings in three sets of clutches are copper based powder metallurgy friction

linings (6 PCS for each). The internal friction linings are made of 65Mn (5 PCS for each), with 0.5

mm concavity. When assembling, the convex surface shall face the piston end and make sure to

rotate the friction linings manually after assembly for inspection.

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Fig. 2-7

1. Constant mesh gear 2. Centrifugal emptying valve 3. Clutch housing 4. Piston

5. Driving friction lining 6. Driven friction lining 7. Driven gear 8. Spring 9. Piston ring

10. Cylinder oil inlet passage 11. Lubricating oil passage 12. Seal ring

2. Working principle

When working: the transmission oil from the transmission control valve flows through the oil

passage in the transmission box and the big end cap and to the cylinder via the inlet end cover and

clutch shaft that will make the piston move forward, compress the driving and driven clutch plates,

and output the power via the driven gear that has been integrated with the clutch housing.

When stop working: The pressure oil will be cut off; the transmission oil in the cylinder returns via

the oil port; the piston returns via the return spring; the driving and driven clutch plates separates

and the gear idles.

2.3.5 Structure and principle of automatic emptying valve (oil drain valve)

After the clutch cylinder cut off the oil supply, the clutch housing will continue to rotate with the

shaft under the action of inertia force, and the transmission oil in the cylinder will move from the

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inside to the outside under the action of centrifugal force which will generate pressure at the

circumferential edge of the cylinder and a thrust for the poison return, therefore hindering the rapid

separation of the clutch. In order to remove the centrifugal pressure from the oil inside the rotating

cylinder, an automatic emptying valve shall be set on the clutch housing.

Fig. 2-8

1 Piston 2 Clutch cylinder 3 Steel ball

When the clutch is engaged:

The pressure oil flows into the cylinder and flows out from the oil drainage hole via the pore

passage between the steel ball and the pore. At this point, pressure difference will be formed at the

front and the back of the steel ball. Under the action of this pressure difference, the steel ball will be

pushed to the oil drainage hole to cover it. When the oil drainage stops, the oil pressure in the

cylinder will rise.

When the clutch is released:

The cylinder connects with the return oil passage to release the pressure. At this point, the steel ball

will no longer be pushed by the pressure oil and will move outward under the action of the

centrifugal force, then, the oil drainage hole will open. The oil in the cylinder flows out from the oil

drainage hole via the pore passage between the steel ball and the pore, which will help the quick

return of the cylinder piston.

When the clutch is engaged When the clutch is released

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2.4 Oil supply system

2.4.1 Structure and working principle of transmission & torque converter

oil supply system

1. Structure of oil supply system

The oil supply system is an important component of the hydro-mechanical transmission system,

which generally consists of transmission pump, transmission control valve, oil filter, radiator, oil

pan and pipeline, etc.

Fig. 2-9 Composition of oil supply system

1. Relief valve 2. Secondary filter 3. Transmission pump 4. Torque converter

5. Radiator 6. Speed change valve 7. Oil pan 8. Primary filter

2. Working principle of oil supply line

When the pump impeller of the torque converter is running, the driving gear will drive the operation

of the oil pump to suck oil from the tank and output the pressure oil, which will flow into the torque

converter combination valve. The torque converter combination valve consists of transmission

pressure valve, inlet pressure valve and constrictor. The working oil to the combination valve

ensures sufficient oil for operation first and then is transmitted to the torque converter via the

transmission pressure valve under the action of the transmission pressure valve. The oil pressure for

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transmission control and the oil pressure at torque converter inlet are controlled by the transmission

pressure valve and inlet pressure valve, with oil pressure of 1.1~1.5 MPa and 0.5~0.6 MPa

respectively. If the oil pressure at torque converter inlet exceeds the setting value of the inlet

pressure valve, the valve port will open and the oil will spill out for oil spray of the transmission

and the torque converter. Torque converter outlet pressure valve will keep the pressure at torque

converter outlet within 0.05~0.15 MPa. The oil from the outlet pressure valve will flow through the

radiator to the transmission lubrication system.

Fig. 2-10 Schematic diagram for the oil supply of transmission & torque converter system

2.4.2 Introduction to oil supply system main components

1. Structure and working principle of hydraulic torque converter

YJ315LG-1 hydraulic torque converter is a single-stage single-phase three-element hydraulic torque

converter. This series of torque converter as shown in Fig. 2-11 consist of energy conversion

elements (impeller, turbine, guide pulley), power input/output elements (elastic plate,wheel cover,

turbine shaft, output flange), fixed supporting element (housing), hydraulic parts and other

accessories, etc.

Inlet pressure valve

Torque converter

combination valve

Torque converter

Transmissi

on pressure

valve

Cooler

Lubrication Shower

1st and 3rd gear clutch 2nd and 4th gear

clutch

Reverse gear clutch

Reverse gear

Neutral gear

1st and 3rd gear

2nd and 4th gear

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Fig. 2-11 Structure and schematic diagram of torque converter

1. Elastic plate 2. Turbine 3. Impeller 4. Guide pulley

5. Guide pulley seat 6. Turbine shaft 7. Output flange.

(1) Power input part

The drive plate, wheel cover and impeller constitute the power input part of the torque converter.

The wheel cover connects with the drive plate via rubber damping block or elastic plate, and the

drive plate connects with the engine flywheel housing via screws.

When the engine is running, the flywheel will drive the rotation of wheel cover via the drive plate.

The wheel cover is firmly connected to the impeller with bolts and sealed at the joint surface with

O-rings. One end of the input part is supported on the center hole of the diesel engine flywheel

housing by the shaft end of the wheel cover, and the other end is supported on the guide pulley seat

by the bearing of impeller.

YJ315LG-1 torque converter has also been equipped with PTO port. A part of power from the diesel

engine is directly transmitted to the pump shaft gear via the transfer gear refitted on the impeller

and drives the operation of gear pump by the pump shaft, etc.

(2) Power output part

The turbine, driving shaft, driving gear, output gear and output shaft together constitute the power

output part of the torque converter. The turbine output shaft is supported at two points. That’s, the

left end is supported on the torque converter wheel cover by needle roller bearing, and the right end

is supported on the torque converter housing by ball bearing. The power from turbine output shaft is

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transmitted via driving gear to the output gear with which the driving gear is meshed, and then to

the output shaft by the output gear.

(3) Fixed supporting part of guide pulley

Guide pulley is fixed on the guide pulley seat via the splined joint, and the guide pulley seat is fixed

on the torque converter housing with screws.

(4) Sealing part of circulating circle

YJ315LG-1 hydraulic torque converter uses three kinds of seals:

● O-ring is used at the joint of wheel cover and impeller to prevent the leakage of liquid in the

circulating circle along the joint.

● Alloy cast iron seal ring is used between the impeller hub and the guide pulley seat to prevent

the leakage of oil at the bearing seat.

● Skeleton oil seal is used at the middle part of flywheel housing and the impeller hub. Note that

the lips of the skeleton oil seal shall face to the incoming flow when assembling.

2. Transmission control valve

The transmission control valve is mainly composed of speed change valve and power shut-off valve,

etc. When pulling the speed change valve lever outwards to the limit, the reverse gear will be

engaged, and when pushing it inwards, neutral gear, 1st gear and 2nd gear will be engaged

successively. The valve body has also been equipped with power shut-off valve, which will shut off

the power oil to the transmission during braking to ensure more reliable braking performance.

Fig. 2-12 Transmission control valve

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1. Power shut-off valve 2. Main pressure measuring port 3. Speed change valve oil inlet

4. Speed change valve lever 5. 1st and 3rd gear lubricating oil passage 6. 1st and 3rd gear

pressure oil passage 7. 2nd and 4th gear pressure oil passage 8. 2rd and 4th gear lubricating oil

passages 9. Reverse gear lubricating oil passage 10. Reverse gear pressure oil passage

11. Oil sprayer port 12. Cooling oil port

(2) Relief valve

The relief valve is mainly composed of transmission pressure valve and torque converter inlet

pressure valve, etc. The speed change valve controls the transmission control pressure (1.1~1.5

MPa); the torque converter inlet pressure valve controls the torque converter inlet oil pressure

(0.5~0.6 MPa). The relief valve is equipped with an oil passage which can be used to lubricate the

torque converter internal gear. When the oil supply pressure in the system is too high, the overflow

valve in the relief valve will open and release pressure via the pressure relief vent.

Fig. 2-13 Relief valve

1. Pressure adjusting bolt 2. Pressure relief vent 3. Lubricating oil port of torque converter

internal gear 4. Torque converter oil inlet 5. Overflow valve 6. Transmission control valve oil

inlet 7. Relief valve oil inlet 8. Torque converter inlet oil pressure adjusting bolt

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2.5 Transmission Operation and Maintenance

2.5.1 Installation and Application Notices for Transmission

(1) When installing transmission, ensure the input share the same axis with the torque converter

output and the transmission output share the same axis with the input of front/rear axle.

(2) Transmission, after installed to the vehicle, shall be filled with about 45L of 6# hydraulic

transmission oil from oil filler, and the oil level shall be checked 5 min after starting the engine,

which shall reach to the level of oil dipstick. Before and after working every shift, always check the

oil level in the transmission carefully.

(3) The gear change in transmission from forward gear to reverse

gear or vice versa as well as between high and low gears must be

carried out after parking, but the change between 1st and 2

nd gear or

between 3rd

and 4th

gear can be done while driving.

(4) Attention shall be paid to maintain the operating oil pressure at

1.1~1.5MPa during transmission operation, and the outlet oil

temperature of torque converter shall be generally not more than

105°C and will not exceed 115°C in the short run, together with the

oil temperature at the transmission oil sump not larger than 100°C.

(5) Each control handle and mechanism shall be flexible without

seizure, and gearshift must be accurate with obvious tactility.

(6) When depressing the brake pedal with engine throttle full open,

the vehicle shall not move.

(7) Appropriate adjustment must be done to parking brake to make

sure it will work reliably.

Fig. 2-14

2.5.2 Maintenance of Transmission

(1) Change oil in the transmission of new vehicle for the first time after the vehicle travels for 100 h

and thereafter perform this operation every 500 h. The oil to be filled shall be 6# (8#) hydraulic

transmission oil with filling amount of about 38L; the oil level shall be checked within 5 min after

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the engine is started and then runs at idling, and the level of oil dipstick shall apply. Before and after

working every shift, always check the oil level in the transmission carefully.

(2) Attention shall be paid to maintain the operating oil pressure at 1.1~1.5MPa during transmission

operation, and the outlet oil temperature of torque converter shall be generally not more than 105°C

and will not exceed 115°C in the short run.

(3) New transmission, after installed to the vehicle, shall experience 12 h running-in, 2 h for each

gear, and the load during which shall not exceed 70% of rated load. Meanwhile, note the oil

temperature, oil level and the fastening of bolts. After the period of running-in, wash transmission

oil sump and the oil filter screen.

(4) The gear change in transmission from forward gear to reverse gear or vice versa as well as

between high and low gears must be carried out after the vehicle is stopped, but the gear change

between 1st and 2

nd gear or between 3

rd and 4

th gear can be done while the vehicle is running.

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3 Removal of Transmission

3.1 Removal of assembly components

Preparation for removal:

(1) Fully clean the mud and dirt on the transmission.

(2) Remove drain plug to drain transmission oil.

Hydraulic transmission oil: about 45L.

(3) Prepare a stable transmission mounting bracket.

Transmission: about 200Kg

3.1.1 Removal of oil filler pipe and filter

Fig. 3-1

1 Oil dipstick 2 Oil filler pipe

3 Bolt

1. Remove oil dipstick and the bolts fastening oil

filler pipe and transmission body, and then

disassemble oil filler pipe and O-ring.

NOTE:

Protect O-ring.

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Fig. 3-2

1 Filter

2. Disassemble filter housing, and remove O-ring,

6 bolts, filter cover and shim.

Fig. 3-3

1 Filter element

3. Take filter element out.

Fig. 3-4

1 Parking brake

2 Fixing bolt

3.1.2 Removal of parking brake

assembly

1. Disassemble the bolts connecting parking

brake and transmission body to take down the

parking brake.

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Fig. 3-5

1 Lock plate

2 Bolt

2. Disassemble the lock plate and fixing bolts

from rear front output flange; remove pressure

plate and O-ring.

Fig. 3-6

1 Oil seal cover 2 Oil seal

3 Output shaft flange 4 Dust cover

5 Brake caliper & disc

3. Remove output shaft flange, brake caliper &

disc and dust cover with hands. Disassemble

the bolts connecting oil seal cover and

transmission body, remove oil seal cover and

adjusting shim and take out oil seal from oil

seal cover.

Fig. 3-7

1 Bolt

2 Transmission control valve

3.1.3 Removal of transmission control

valve

1. Disassemble the bolts connecting transmission

control valve and transmission, and then

remove upper paper washer, bottom plate and

lower paper washer in turn.

NOTE:

● Ensure cleanness and protection after

removing the transmission control valve.

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● Protect sealing surface and gasket.

Fig. 3-8

1 Bolt 2 Cover plate

3 Breather

3.1.4 Removal of breather and cover

plate

1. Disassemble breather and take out flap, copper

pipe and 5 Labyrinth gaskets.

Disassemble connecting bolts from the cover plate

to remove paper washer.

Fig. 3-9

1 Round nut 2 Round nut washer

3 Washer

3.1.5 Removal of input flange

1. Disassemble round nuts from input shaft with a

special socket to remove round nut washer, washer,

input flange and dust cover.

Fig. 3-10

1 Bolt

2 Oil sump

3.1.6 Removal of oil sump

1. Lay transmission body sideways, and

disassemble the bolts connecting oil sump and

transmission body to remove the oil sump.

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Fig. 3-11

1 Iron wire 2 Fastening screw

3 Fork shaft

3.1.7 Removal of high/low gearshift

fork mechanism

1. Disassemble the iron wire on high/low

gearshift fork mechanism, unscrew fastening

screws and remove fork shaft and the fork.

Fig. 3-12

1 Bolt

2. Unscrew screw plug and washer, remove steel

balls and spring and then disassemble oil seal.

Fig. 3-13

1 Lock plate 2 Bolt

3 Pressure plate 4 Output shaft flange

3.1.8 Removal of output shaft

1. Disassemble lock plate, unscrew the fixing

bolts of rear output flange, remove pressure

plate and O-ring and then take out the output

shaft flange, dust cover and oil seal by hand.

NOTE:

Protect O-ring.

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Fig. 3-14

1 Bolt

2 Output rear end cover

2. Unscrew the bolts connecting output rear end

cover to transmission body, disassemble output

rear end cover and take it out together with the

whole output shaft backwards.

Fig. 3-15

1 Output shaft 2 Thrust ring

3 Gear (output shaft high gear) 4 High/low

gear sliding sleeve

5 Gear (output shaft low gear)

3. Remove bearing, gear, high/low gear sliding

sleeve, spacer ring and thrust ring from the

shaft.

NOTE:

Gear wheel can be taken out from the bottom

hole of the transmission body.

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Fig. 3-16

1 Input shaft end cover 2 Reverse shaft end

cover

3 Intermediate gear shaft end cover

3.1.9 Removal of three sets of clutch

gear shafts

1. Lay transmission body flat with the big end cap

surface up, disassemble 3 oil inlet end covers

and remove washers. Remove all seal rings on

the three sets of clutch gear shafts.

NOTE:

Safekeep the seal rings.

Fig. 3-17

1 External oil seal sleeve

2. Remove all external oil seal sleeves inside each

cover.

Fig. 3-18

1 End cover 2 Hoisting bolt

3 Bearing cup

3. Firstly use jackscrew to jack up big end cap,

secondly screw two hoisting bolts into the

mounting holes of the end cover, and finally

operate the crane and disassemble the big end

cap to remove 3 bearing cups wherein.

About 15kg.

NOTE:

The hoisting operation shall be done slowly.

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Fig. 3-19

1 Input shaft assembly

4. Take out input shaft assembly vertically.

NOTE:

Tap lightly on the rear end when it is hard to

take the shaft out.

Fig. 3-20

1 Reverse shaft assembly

2 Countershaft assembly

5. Take out countershaft assembly and reverse

shaft assembly in turn.

Fig. 3-21

1 Stop plate 2 bolt

3 Adjusting screw

6. Erect transmission body, disassemble hexagon

bolts and stop plates on 3 small end covers at

the front and unscrew adjusting screws.

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Fig. 3-22

1 Bolt 2 End cover

3 Adjusting ring 4 Paper washer

7. Disassemble fixing bolts of the end cover to

remove the end cover.

8. Remove 3 paper washers, 2 adjusting rings,

one oil seal (input shaft) and 3 bearing cups

separately.

3.2 Removal of assembly

3.2.1 Removal of transmission control

valve

Fig. 3-23

1 Plug

1. Unscrew the plug and shim from valve stem

locating lock pin and take out spring and steel

ball.

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Fig. 3-24

1 Snap ring

2. Disassemble snap rings at the front and rear of

the valve stem, push forward valve stem, and

squeeze out 2 oil seals and adjusting washers at

the front of the valve holes.

Fig. 3-25

1 Oil seal 2 Adjusting washer

3 Valve stem

3. Then push backward the valve stem, squeeze

out 2 oil seals and adjusting washers at the rear

end of the valve hole and take out the valve

stem.

Fig. 3-26

1 Screw plug

4. Disassemble the screw plug at the front end of

brake valve stem and take out spring seat,

O-ring and spring.

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Fig. 3-27

1 Screw plug 2 O-ring

3 Leather cup 4 Brake sliding valve

5. Disassemble screw plug from the rear end of

valve hole, remove O-ring, and push out brake

valve stem and leather cup.

3.2.2 Removal of three sets of clutch

gear shaft assemblies

NOTE:

● The removal of input shaft assembly shall be

carried out from the front end of shaft to the

rear end. The removal of reverse gear shaft and

countershaft assemblies shall be carried out

from the rear end of shaft to the front end.

● The method of disassembling countershaft and

reverse gear shaft assemblies is similar to that of

input shaft assembly, and the only difference lies

in the direction of clutch. Moreover coMPared

with the input shaft assembly, the countershaft

assembly has one more gear and the reverse gear

shaft assembly one more shaft sleeve. Take input

shaft assembly as example to introduce the

disassembling procedure, and the others will not

be repeated here.

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Fig. 3-28

1 Bolt 2 Stop pad

3 Shaft end baffle

1. Disassemble connecting bolts and stop pad

from shaft end to remove shaft end baffle.

Fig. 3-29

1 Piston ring

2 Internal oil seal sleeve

2. Remove internal oil seal sleeve and 2 piston

rings on it.

Fig. 3-30

1 Shaft sleeve

2 Bearing

3. Remove bearings from both ends of the shaft

and shaft sleeve from the front end of the shaft.

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Fig. 3-31

1 Clutch external drum 2 Bolt

3 Stop pad 4 Gear wheel

4. Remove clutch external drum from the shaft

and disassemble 8 bolts and 4 stop pads as well

as a gear wheel.

Fig. 3-32

1 Emptying valve

5. Disassemble automatic emptying valve (oil

drain valve) base and steel ball on the clutch

housing.

Fig. 3-33

1 Retainer ring

2 External end cover

6. Disassemble retainer ring and take out external

end cover from the clutch. Take out friction

lining: steel disc and wafer.

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33

Fig. 3-34

1 Special tools 2 Shaft elastic retainer ring

3 Spring 4 Piston

7. Remove retainer ring from housing internal

hub with special tools.

8. Disassemble spring seat, spring and piston.

Fig. 3-35

1 Oil seal ring

9. Disassemble oil seal ring from the piston.

10. Remove O-ring from the housing internal hub.

Fig. 3-36

1 Pinion

11. Press pinion out from the shaft and

disassemble the snap rings at both ends and 2

bearings.

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4 Refitting of Transmission

4.1 Refitting of assembly

NOTE:

Wash all parts before refitting.

4.1.1 Refitting of clutch shaft assembly

NOTE:

Three sets of clutch assemblies are of similar structure. Take input shaft assembly as example

to introduce refitting procedure and the others will not be repeated here.

Fig. 4-1

1 Automatic emptying valve

1. Assemble steel ball and automatic emptying

valve (oil drain valve) base.

Fig. 4-2

1 Oil seal ring

2. Assemble O-ring on the housing internal hub.

3. Assemble oil seal ring on piston, apply clean oil

and put the piston into the housing.

NOTE:

● When installing oil seal ring, the sealing surface

shall be placed toward pressure oil surface.

● The oil seal ring is made of rubber and shall be

free of damages caused by crush during assembly.

● The opening width of piston ring shall be within

0.05~0.1mm.

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Fig. 4-3

1 Special tools 2 Retainer ring

3 Spring seat 4 Spring

4. Put lower spring seat, spring and upper spring

seat in the internal hub in turn and use special

tools to compress the spring in order to assemble

retainer ring.

Fig. 4-4

1 Outer friction lining

2 Internal friction lining

5. There are 6 clutch driving plates in all, which are

friction linings made of copper based powder

metallurgy, and 5 driven plates made of steel

with 0.5 mm concavity; make sure to put the

concave surface towards piston end while

refitting.

NOTE:

● The number of outer friction linings for the

three sets of clutches is 6.

● The number of internal friction linings for the

three sets of clutches is 5.

Fig. 4-5

6. Assemble 11 friction linings to the housing in the

sequence of outer gear, inner gear and outer gear

as shown in Fig. 4-5.

NOTE:

● If abrasion that occurs during the usage of outer

friction lining is more than 2/3 in the depth of

pattern groove, replacement is required

immediately.

● Replace the corresponding friction lining only

Outer friction lining

Internal friction lining

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36

and make sure its number and refitting order is

correct.

Fig. 4-6

1 Retainer ring

2 External end cover

7. Assemble external end cover and snap ring.

Fig. 4-7

1 Bearing

2 Retainer ring

8. Assemble the pinion with snap ring and 2

bearings to the shaft in place.

Fig. 4-8

1 Gear wheel 2 Bolt

3 Stop pad

9. Align gear wheel with the cylindrical pin on the

clutch housing, fasten them with bolts and

meanwhile assemble 4 stop pads to avoid

looseness.

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Fig. 4-9

1 Pinion

10. Lay clutch flat and insert the pinion after

aligning the teeth of internal gear friction linings

with a screwdriver.

Fig. 4-10

1 Shaft sleeve

2 Bearing

11. Turn left and right the pinion continuously until

the spline of the pinion is inserted into the

internal tooth of driven plate, insert input shaft to

ensure the clutch is installed in place and

assemble 2 bearings on both ends of the shaft.

NOTE:

When the length of the extending gear on the

spline shaft is equals to the width of shaft sleeve, it

shows that the clutch is installed in place;

otherwise, it means that the internal teeth of some

driven plates deviate and are not engaged with the

pinion.

Fig. 4-11

1 Piston ring 2 Oil inlet passage

12. Assemble 2 piston rings to internal oil seal

sleeve.

NOTE:

● Piston ring is made of cast iron with greater

brittleness, so it needs to be installed with even

force to avoid damage.

● The openings of two seal rings need to be

staggered, and also have a distance from oil inlet

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38

3 Internal oil seal sleeve passage.

Fig. 4-12

1 Internal oil seal sleeve

13. Assemble internal oil seal sleeve to shaft.

NOTE:

● Internal oil seal sleeve shall be installed to shaft

by heating evenly in oil at the temperature of

100~150°C.

● Wear heat insulation gloves while refitting, and

the picture is only for reference.

Fig. 4-13

1 Shaft end baffle 2 Stop pad

3 Bolt

14. Install shaft end baffle, stop pad and bolts.

Fig. 4-14

1 Reverse gear shaft assembly

2 Countershaft assembly

4.2 Refitting of assembly components

4.2.1 Assembly of three sets of gear

shafts

1. Lay transmission body flat, put the assembled

reverse gear shaft assembly to the mounting

position in the transmission body and then put in

countershaft assembly.

NOTE:

When refitting, clutch shall be installed by

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39

rotating.

Fig. 4-15

1 Input shaft assembly

2. Put the assembled input shaft assembly to the

mounting position in the transmission body.

NOTE:

Make sure all sets of gears are correctly engaged.

Fig. 4-16

1 Big end cap

3. Install big end cap to the transmission body, and

fasten the bolts connecting end cover and

transmission body.

About 41.5kg.

NOTE:

Check and replace with new gasket.

Fig. 4-17

1 External oil seal sleeve

4. Install external oil seal sleeves to each cover.

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Fig. 4-18

1 Input shaft end cover 2 Reverse shaft

end cover

3 Countershaft end cover

5. Install three sets of oil inlet end covers, and

fasten the bolts connecting end cover and

transmission body.

NOTE:

● Check and replace with new gasket.

Fig. 4-19

1 1st/reverse gear end cover

2 Neutral gear end cover

● Three oil inlet end covers have the same

appearance but different inside oil passages. The

oil passage of 1st and reverse gears are identical

but different from that of neutral gear.

Fig. 4-20

4.2.2 Refitting of input flange and rear

end cover

1. Install oil seal into input shaft oil seal seat, install

the bearing of input shaft in place by tapping,

and measure and adjust the axial clearance of

input shaft.

Adjusting method:

Use depthometer to measure the depth H from

bearing (cone and cup) to the surface of the

transmission body as well as the height h of oil

seal seat step; select and add adjusting shim

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(δ=0.1mm) to ensure H-h-δ=0.1~0.15mm.

Fig. 4-21

1 Round nut washer 2 Washer

3 Round nut

2. Assemble input flange as well as washer, round

nut and washer in turn and fasten round nuts

using special tools.

Fig. 4-22

1 Adjusting screw

2 Adjusting ring

4.2.3 Assembly of countershaft and

reverse gear shaft rear end cover

1. Install bearing mounting paper washer, bearing

cup and adjusting ring to the rear ends of reverse

gear shaft and countershaft. Install the rear end

covers of reverse hear shaft and countershaft and

fasten them with bolts. Tap adjusting ring in

place through the hole on the rear end cover.

Fig. 4-23

1 Stop pad

2. Adjust the clearance of taper roller bearing

supporting at both ends of the shaft through

rotating the screw in the center of rear end cover.

Install stop pad to fasten the adjusting screw.

Adjusting methods:

Turn the adjusting screw to the limit and then

return by about 15° (the screw pitch is 1mm and

the clearance required shall be 0.25~0.5mm).

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3. Input flange shall be rotated freely.

Fig. 4-24

1 Output shaft assembly

2 Low-speed gear

4.2.4 Assembly of output shaft

1. Assemble bearing, gear, high/low gear sliding

sleeve, spacer ring and thrust ring of the output

shaft, and put them into transmission body.

NOTE:

Low-speed gear can be put into transmission body

from its bottom hole.

Fig. 4-25

1 Bolt 2 Output rear end cover

3 Pressure plate 4 Bolt

2. Tighten the bolts connecting output rear end

cover and transmission body and install 2 oil

seals and dust covers.

3. Install O-ring, pressure plate and fixing bolts that

used to fix rear output flange, and fit lock plate.

Fig. 4-26

1 Iron wire

2 Fixing bolt

4.2.5 Assembly of high/low gearshift

fork mechanism

1. Insert fork shaft, install fork, put fork shaft in the

neutral position, set sliding sleeve to the spline

tooth in the middle of output shaft, align fork

shaft with the thread hole on the fork, then fasten

screws and tighten with iron wire.

NOTE:

The high/low speed lever includes high, neutral

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and low gears, and the travel between two

adjacent positions is 15mm.

Fig. 4-27

1 High/low gearshift fork 2 Screw plug

3 Steel ball 4 Spring

5 Oil seal

2. Install spring and steel ball, fasten screw plug

and washer and install gearshift shaft oil seal.

Fig. 4-28

1 Bolt

4.2.6 Assembly of oil sump

1. Install gasket and fasten the bolts connecting oil

sump and transmission body.

NOTE:

● Check and replace gasket.

● The bolts shall be fastened diagonally in several

steps.

Fig. 4-29

1 Bolt

4.2.7 Assembly of transmission control

valve

1. Install upper paper washer, bottom plate and

lower paper washer to transmission control

valve.

2. Erect transmission body and install transmission

control valve to the transmission body.

NOTE:

The bolts shall be fastened diagonally in several

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steps.

Fig. 4-30

1 Cover plate

2 Breather

4.2.8 Assembly of breather and cover

plate

1. Install cover plate and paper washer, fasten the

bolts on them and screw on the breather.

NOTE:

The bolts shall be fastened diagonally in several

steps.

Fig. 4-31

1 Oil seal cover 2 Oil seal

3 Output shaft flange 4 Dust cover

5 Brake caliper disc

4.2.9 Assembly of parking brake

assembly

1. Install oil seal cover to transmission body.

Fig. 4-32

1 Pressure plate

2 O-ring

2. Install O-ring and pressure plate.

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Fig. 4-33

1 Lock plate

2 Bolt

3. Screw up the fixing bolts on the output flange

and assemble upper lock plate.

Fig. 4-34

4. Install parking brake and fasten connecting bolts.

Fig. 4-35

1 Filter

2 Oil filler pipe

4.2.10 Assembly of oil filler pipe and

filter

1. Install filter with O-ring and fix them to

transmission body.

2. Install oil filler pipe and O-ring, and fasten

connecting bolts.

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5 Service Tools for Transmission

Table 5-1

Special tools Tool name Location to be used Remarks

Transmission mounting

bracket

To support and tilt

transmission

If not available, a

disassembly and assembly

platform can be set up.

Hoisting tools End cover M10

Socket Round nut on the

input shaft

Disassembly and

assembly tool of clutch

spring

Three sets of clutch

springs

Depth meter Input shaft Spec: 0.02/0~200

Transmission pressure

joint

Pressure joint of

relief valve 6410006223

Pressure testing hose

Use with pressure

joint and pressure

gauge.

4030000368

Pressure gauge with a

gauge of 25 bar 6430000943

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6 Common Fault Diagnosis and Troubleshooting

Table 6-1

Symptoms Probable causes Solution

1. Weak traveling and gear

shift seizure

Low oil level, and empty pump Check if the oil level is below

oil dipstick and add oil

Oil suction filter element falls

off or is blocked up

Check, wash and replace after

removal

The inner layer of oil suction

pipe is peeling off

Check and replace after

removal

Air enters oil suction pipe Check

Relief valve is adjusted to a too

low pressure

Check, adjust and replace valve

Pump abrasion and oil leakage Replace pump

The oil drain pipe of torque

converter is blocked up

Check, wash and replace

The opening pressure of

overflow valve is too low

Raise the opening pressure

Transmission clutch slipping Check transmission after

removal

Piston oil seal ring has abrasion

or damage

Replace

Oil passage from relief valve to

pilot valve is blocked up

Check pipeline

Transmission shaft end ring or

sleeve shows abrasion

Replace seal ring and sleeve

2. High oil temperature Low oil level, and empty pump Check oil level and add oil

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Symptoms Probable causes Solution

Oil suction filter element falls

off or is blocked up

Check, wash and replace after

removal

The inner layer of oil suction

pipe is peeling off

Check and replace after

removal

Air enters oil suction pipe Check

Pump abrasion and oil leakage Replace pump

Low transmission pressure and

clutch slipping

Raise pressure or find out

causes

Torque converter has large

inside leakage

Check torque converter after

removal

Oil temperature gauge and

sensing plug are broken

Replace

3. Low oil pressure

Low oil level, and empty pump Check oil level and add oil

Oil suction filter element falls

off or is blocked up

Check, wash and replace

Air enters oil suction pipe or its

inner layer is peeling

Check and replace

Transmission shaft ring or

sleeve shows abrasion

Replace seal ring and sleeve

Piston oil seal ring has abrasion

or damage

Replace

The spring of relief valve is

broken

Check and replace valve

Pump abrasion and oil leakage Replace pump

Pressure valve is adjusted to a

too low pressure

Adjust again

Oil passage from relief valve to Check pipeline

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Symptoms Probable causes Solution

pilot valve is blocked up

4. Abnormal sound

Propeller shaft is installed in a

wrong direction

Follow the direction of arrow

Vortex appears when opening

relief valve

Replace relief valve

Internal parts are damaged or

gears have poor accuracy

Check after removal

5. High/low gear is out of

mesh

The positioning steel ball of

fork is abraded flat causing the

ball unable to work normally

Check and replace

Steel ball shows serious

abrasion

Check and replace

Spring is damaged Check and replace

The depth of positioning hole

for locking screw is insufficient

causing the fork cannot be

locked by screw securely

Check and replace

Locking screw is sliding, etc. Check and replace

6. Only one gear is normal

and others have low

pressure

Oil inlet end cover is installed

in a wrong way

Exchange

The oil seal ring or piston ring

of other two gears are damaged

Check and replace

7. Only one gear is

available, and the vehicle

can run even in the neutral

gear

The clutch of one gear is burnt

out and friction lining is unable

to separate

Check and repair

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