Axle Shafts - Rear 3500 Series

2002-03 DRIVE AXLES

Differential - Rear - Quadrasteer - Silverado, Sierra

MODEL IDENTIFICATION

Vehicle model can be identified by fifth character of Vehicle Identification Number (VIN), stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

MODEL IDENTIFICATION

DESCRIPTION

Quadrasteer(tm) is a 4-wheel steering system that dramatically enhances low speed maneuverability, high speed stability, and towing capability. The system is an electrically powered rear wheel steering system comprised of the following components:

z A steerable, solid hypoid rear axle. z A steering wheel position sensor located at the base of the steering column. z A rear wheel position sensor located below the rear wheel steering motor on the rear steering gear. z An electric motor driven actuator. z A rear wheel steering control module. z A combined yaw rate sensor/ lateral accelerometer sensor. z Three hall effect switches in the motor assembly. z A mode select switch on the dash. z A heavy duty wiring harness and fuse. z A Service 4 Wheel Steer indicator in the IPC. z A shorting relay in the rear wheel steering gear motor. z A power relay in the rear wheel steering control module.

The rear wheel steering control module has these inputs:

z Battery voltage.

Series (1) Model"C" 2WD Sierra & Silverado"K" 4WD Sierra & Silverado(1) Fifth character of VIN.

NOTE: This article covers Steering Mechanical Rear information only. For Steering Electronic Rear information see ELECTRONIC - REAR - SIERRA , SILVERADO, TAHOE article.

2003 Chevrolet Silverado 1500

2002-03 DRIVE AXLES Differential - Rear - Quadrasteer - Silverado, Sierra



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April-29-08 9:46:32 AM Page 1 2005 Mitchell Repair Information Company, LLC.

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z Switched battery voltage. z Rear wheel steering mode switch signal. z Steering wheel position sensor analog. z Steering wheel position sensor phase A z Steering wheel position sensor phase B z Steering wheel position sensor marker pulse. z Rear wheel position sensor position 1. z Rear wheel position sensor position 2. z Vehicle speed signal. z Class 2 data. z Yaw rate signal. z Lateral accelerometer signal. z Rear wheel steering motor actuator hall A. z Rear wheel steering motor actuator hall B. z Rear wheel steering motor actuator hall C.

The rear wheel steering control module has these outputs:

z Rear wheel steering motor actuator phase A control. z Rear wheel steering motor actuator phase B control. z Rear wheel steering motor actuator phase C control. z Rear wheel steering motor shorting relay voltage. z Rear wheel steering module class 2 serial data. z 4- Wheel steer mode indicator supply voltage. z 4- Wheel steer tow mode indicator supply voltage. z 2- Wheel steer mode indicator supply voltage. z Rear wheel steering mode select switch supply voltage. z Steering wheel position sensor 5 volt reference. z Rear wheel position sensor 5 volt reference. z Rear wheel steering motor hall sensor 12 volt reference. z Rear wheel steering motor shorting relay voltage.

Separate connectors to the rear wheel steering control module are provided for the following 4 capacities:

z Vehicle battery power. z The vehicle class 2 , steering wheel position , mode select switch , lateral accelerometer , yaw sensor,

speed sensor signals. z The motor phase power leads. z The motor hall sensors, shorting relay, and rear wheel position sensor signals.



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Fig. 1: Exploded View Of Steerable Rear Drive Axle (9.75" Ring Gear) Courtesy of GENERAL MOTORS CORP.



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Fig. 2: Exploded View Of Steerable Rear Drive Axle (Wheel End) Courtesy of GENERAL MOTORS CORP.

AXLE RATIO & IDENTIFICATION

Rear axle identification is stamped on the forward, right side of axle tube. The first 3 digits indicate rear axle dear ratio, the next digit indicates axle assembly build source code and the next 3 digits indicate the day built.

LUBRICATION

Fill differential with Axle Lubricant (AM P/N 12378557 (Canadian P/N 88901362) or equivalent meeting GM Specification 9986207. Fill differential to within 1/4" (6 mm) below edge of filler hole. If rear drive axle has been drained, fill capacity is 3.0 qts. (2.84 L).



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TROUBLE SHOOTING

See DRIVE AXLE - BASIC TROUBLE SHOOTING (ALL MODELS) article in GENERAL INFORMATION.

REMOVAL & INSTALLATION

AXLE SHAFT & SEAL - OUTER

Removal

1. Release the park brake. Raise and support vehicle. Remove rear tire/wheel assemblies. Remove brake drums or rotors. Remove the rear steering gear assembly. See STEERING GEAR ACTUATOR & DIFFERENTIAL COVER .

2. Remove the steering knuckle assembly. See STEERING KNUCKLE ASSEMBLY . 3. Remove the lock clip from the axle shaft end. See Fig. 3 . The lock clip is spring loaded and fits securely

in the axle shaft slot and may need to be pushed off the shaft end with a screw driver or similar tool. Pushing the axle shaft inwards towards the gears my help in removal of the lock clip. Remove the axle shaft. Using appropriate seal puller, remove the axle shaft seal. See Fig. 4 .

NOTE: When removing the axle shaft DO NOT rotate the shaft. Rotating the shaft will cause the gears to move. Misalignment of the gears will make the assembly difficult.



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Fig. 3: Removing Axle Shaft Retaining Clip Courtesy of GENERAL MOTORS CORP.



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Fig. 4: Removing & Replacing Outer Axle Shaft Seal Courtesy of GENERAL MOTORS CORP.

Installation

1. Clean axle shaft seal seat. Using appropriate seal installer, install the axle shaft seal. See Fig. 4 . Install the axle shaft. Install the spring loaded lock clip to the axle shaft end. Install the steering knuckle assembly. See STEERING KNUCKLE ASSEMBLY . Install the rear steering gear actuator and differential cover. See STEERING GEAR ACTUATOR & DIFFERENTIAL COVER .

2. Install the wheel/tire assemblies. Tighten fasteners to specification. See TORQUE SPECIFICATIONS .



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Fill differential with lubricant. See LUBRICATION . Lower the vehicle.

AXLE SHAFT & SEAL - INNER

Removal

Required Tools, J 33049 Camshaft Bearing Service Set and J 45177 Differential Seal Installer - Inner

1. Raise the vehicle. 2. Remove the tire and wheel assembly. 3. Remove the axle shafts. 4. Remove the differential assembly. 5. Install the smallest expanding driver (3) and the small driving washer (1) onto the expander assembly (2). 6. Align the separation lines between the expanding driver and the expander assembly. 7. Assemble the expander assembly (2) onto the driver bar extension (1). 8. Assemble the drive bar extension onto the driver bar. 9. Insert the J 33049 into the axle tube and through the axle shaft seal.

10. While holding the expander assembly nut, turn the driving bar clockwise until the expanding driver is snug against the axle shaft seal.

11. Drive out the seal using the J 33049 and a hammer.

Installation

Required Tools, J 33049 Camshaft Bearing Service Set and J 45177 Differential Seal Installer - Inner

1. Assemble the drive bar extension onto the drive bar of J 33049. 2. Insert the J 33049 into the opposite side axle shaft tube. 3. Install the J 45177 onto the J 33049. 4. Insert the axle shaft seal into the axle tube. 5. Install the J 45177 (1) and the J 33049 (2) over the axle shaft seal. 6. Drive the axle shaft seal into the axle tube using the J 45177 , the J 33049 and a hammer. 7. Install the differential assembly. 8. Install the axle shafts. 9. Install the tire and wheel assembly.

10. Lower the vehicle.

DIFFERENTIAL CASE & RING GEAR

Removal

1. Raise and support vehicle. Remove steering gear actuator and differential cover. See STEERING GEAR ACTUATOR & DIFFERENTIAL COVER . Remove Axle shafts. See AXLE SHAFT & SEAL .



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2. Loosen the bearing cap bolts. DO NOT remove the bearing cap bolts at this time. Install the Axle Housing Spreader (J-24385-01) onto the axle housing. See Fig. 5 . Install the Guide Pins (J-25025), the Dial Indicator (J-8001-1) and the appropriate dial indicator adapters onto the axle housing.

3. Preload the dial of the dial indicator by pushing it against the edge of the axle housing spreader until the needle of the dial indicator has moved approximately 3/4 of a turn clockwise. Rotate the indicator housing to align the dial indicator needle to ZERO.

4. Spread the axle housing by turning the clevis screw of the axle housing spreader clockwise while observing the dial indicator. Spread the housing just enough to remove the differential assembly. Remove the guide pins. Remove dial indicator and mounting adapters from the axle housing. Remove the bearing cap bolts.

5. Corresponding letters are stamped on the bearing caps and axle housing. The bearing caps must be reassembled in the same position as removed. Remove the bearing caps. Remove the differential assembly. Remove the axle housing spreader.

6. Remove and discard the ring gear bolts. Remove the ring gear from the differential case. Drive the gear off with a brass drift, if necessary. Remove the differential side bearings, if necessary. See DIFFERENTIAL SIDE BEARINGS .

CAUTION: Notice DO NOT spread the axle housing more than 0.015" (0.38 mm). Overspreading the housing may result in component damage.

CAUTION: To prevent personal injury and/or component damage, support the differential case when removing the case from the axle housing. If the case is not supported, the differential case could fall and cause personal injury or damage to the differential case.



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Fig. 5: Removing Differential Case Courtesy of GENERAL MOTORS CORP.

Installation



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1. 2. Install the ring gear to the differential case. Align the holes in the differential case to the bolts holes in the

ring gear. The ring gear bolts use right hand threads. Install the NEW ring gear bolts. Tighten the ring gear bolts alternately and in stages, gradually pulling the ring gear onto the differential case. Tighten NEW ring gear bolts to specification. See TORQUE SPECIFICATIONS . Install the differential assembly.

3. If removed, install differential side bearings. See DIFFERENTIAL SIDE BEARINGS . Install axle housing spreader onto the axle housing. Install the Guide Pins (J-25025), the Dial Indicator (J-8001-1) and the appropriate adapters onto the axle housing.

4. Push the dial indicator stem against the edge of the axle housing spreader and preload the dial indicator until the needle has moved approximately 3/4 of a turn clockwise. Rotate the dial indicator housing to align the dial indicator needle to ZERO.

5. Spread the axle housing by turning the clevis screw of the axle housing spreader clockwise while observing the dial indicator. Spread the housing just enough to install the differential case assembly. Install the differential case assembly. Remove the axle housing spreader, guide pins, dial indicator and adapters from the axle housing.

6. Corresponding letters are stamped on the bearing caps and axle housing. The bearing caps must be reassembled in the same position as removed. Install the bearing caps. Ensure the correct fastener are used in the correct location. Install the bearing cap bolts. Tighten the bearing cap bolts to specification. See TORQUE SPECIFICATIONS .

7. Set side bearing preload. See SIDE BEARING PRELOAD under ADJUSTMENTS. Set ring gear backlash. SeeBACKLASH & FINAL ASSEMBLY under ADJUSTMENTS.

8. Install the axle shafts. See AXLE SHAFT & SEAL . Install steering gear actuator and differential cover. See STEERING GEAR ACTUATOR & DIFFERENTIAL COVER . Install wheel/tire assemblies.

9. Fill the axle with lubricant. Use the proper fluid. See LUBRICATION . Lower vehicle.

DIFFERENTIAL SIDE BEARINGS

Removal & Installation

1. Raise and support vehicle. Remove wheel/tire assemblies. Remove differential case. See DIFFERENTIAL CASE & RING GEAR .

2. Install the Bearing Remover (J-45711) and the Bearing Installer (J-8107-3). See Fig. 6 . Using hydraulic press, remove the differential side bearing. Remove and mark the inboard shims left or right.

3. Determine the shim thickness and preload for the differential assembly. See SIDE BEARING

CAUTION: DO NOT spread the axle housing more than 0.015" (0.38 mm). Overspreading the housing may result in component damage.

NOTE: DO NOT use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener.



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PRELOAD under ADJUSTMENTS. 4. 5. In order to protect the differential case, install the Side Bearing Puller Pilot/Protector (J-8107-3) in the

case on the side opposite of the bearing installation. 6. Install the differential side bearing onto case. Install the Differential Side Bearing Installer (J-24430) and

Universal Driver Handle (J-8092) over the differential side bearing. 7. Drive the differential side bearing into position using the differential side bearing installer and universal

driver handle. 8. Install the differential case assembly. See DIFFERENTIAL CASE & RING GEAR . 9. Install the axle shafts. See AXLE SHAFT & SEAL . Install steering gear actuator and differential cover.

See STEERING GEAR ACTUATOR & DIFFERENTIAL COVER . 10. Fill the axle with lubricant. See LUBRICATION . Install wheel/tire assemblies. Lower the vehicle.



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Fig. 6: Removing Differential Side BearingsCourtesy of GENERAL MOTORS CORP.

PINION YOKE & OIL SEAL

Removal

1. Raise and support vehicle. Mark drive shaft, axle shafts, pinion yoke and output shafts for reassembly. Unbolt drive shaft, and wire aside. Using tape, secure "U" joint bearing caps. Using an INCH-lb. torque wrench, rotate pinion several revolutions. Stop and start rotation several times. Note and record pinion bearing preload.

2. Match mark pinion-to-nut and nut-to-pinion yoke for reassembly purposes. Count and record number of exposed threads on pinion.

3. Hold pinion yoke with Pinion Flange/Yoke Holder (J-8614-01). See Fig. 7 . Remove nut and washer. Using Pinion Flange/Yoke Removers (J-8614-2 and J-8614-3), remove pinion yoke. Pry pinion seal from housing.

Fig. 7: Removing Pinion Flange Courtesy of GENERAL MOTORS CORP.

NOTE: Pinion yoke may also be referred to as pinion flange.

NOTE: If replacing pinion and ring gear, discard original pinion yoke/flange after removal. Replacement pinion, ring gear and pinion yoke/flange are balanced as an assembly.



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Installation

1. Apply a light coat of axle lubricant (GM P/N 12378557) or equivalent meeting GM Specification 9986207, to the lip of the pinion seal. Using Seal Installer (J-45710), install the NEW pinion seal.

2. Align pinion flange marks with marks on pinion. Install the pinion yoke. Seat the pinion yoke onto the pinion shaft by tapping it with a soft-faced hammer until a few pinion shaft threads show through the yoke.

3. Install the washer. Install the NEW pinion nut. Install the pinion flange holder onto the pinion yoke. While holding the J 8614-01 Tighten the pinion nut to specification. See TORQUE SPECIFICATIONS . Install the drive shaft to the rear axle pinion yoke. Inspect and add axle lubricant to the axle housing, if necessary. See LUBRICATION . Lower the vehicle.

REAR WHEEL HUB ASSEMBLY


1. Raise and support vehicle. Remove the wheel/tire assembly. Remove the brake rotor or drum. Remove the axle nut dust cover. Remove the cotter pin and retainer from the wheel drive shaft nut. Remove the wheel drive shaft retaining nut.

2. Remove the rear wheel hub and bearing retaining bolts. Using Axle Remover (J-45859), separate the wheel drive shaft from the wheel hub and bearing. Remove the rear wheel hub and bearing from the vehicle. See Fig. 8 .

3. Install the rear wheel hub and bearing. Install the rear wheel hub and bearing retaining bolts. Tighten bolts to specification. See TORQUE SPECIFICATIONS . Install the wheel drive shaft retaining nut. Tighten nut to specification. Install the retainer and cotter pin to wheel drive shaft nut. Install the dust cap. Install the brake rotor or drum. Install the wheel/tire assembly. Lower the vehicle.



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Fig. 8: Removing Rear Wheel Hub Courtesy of GENERAL MOTORS CORP.

STEERING GEAR ACTUATOR & DIFFERENTIAL COVER



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Removal

1. Release the park brake. Raise the vehicle. Remove the tire/wheel assemblies. Place appropriate drain container under differential housing. Remove the drain plug and drain the fluid from the differential housing.

2. Remove the bolts retaining the steering gear protection shield. Disconnect the electrical connectors from the control module. Disconnect the electrical connector from the rear position sensor.

3. Remove the outer tie rod ends from the steering knuckle. Remove the nuts retaining the outer tie rod ends to the steering knuckles. Using the Steering Linkage Puller (J-24319-B), remove the outer tie rod end from the steering knuckle. Remove the outer tie rod end from the inner tie rod.

4. Disconnect the differential vent hose from the vent tube. Remove the bolts retaining the steering gear actuator and cover to the differential. Remove the steering gear actuator and cover from the vehicle.

Installation

1. Install the steering gear actuator and gasket to the differential. Install the steering gear actuator and cover retaining bolts. Tighten the bolts to specification. See TORQUE SPECIFICATIONS .

2. Connect the electrical connectors to the control module. Install the differential vent hose to the vent tube. Install the drain plug and tighten to specification. See TORQUE SPECIFICATIONS . Fill the differential with fluid. See LUBRICATION .

3. Install the outer tie rod ends to the steering knuckle. Install steering gear shield retaining bolts. See TORQUE SPECIFICATIONS . Install the wheel/tire assembly. Lower the vehicle. Perform a four wheel alignment. See appropriate WHEEL ALIGNMENT article.

STEERING KNUCKLE ASSEMBLY


1. Raise the vehicle. Remove the wheel/tire assembly. Remove the wheel hub and bearing. See REAR WHEEL HUB ASSEMBLY . Remove the upper and lower ball joints. See appropriate article in SUSPENSIONS.

2. Remove the outer tie rod retaining nut and bracket. Disconnect the outer tie rod from the steering knuckle using Steering Linkage Puller (J-24319-B). Fig. 9 . Remove the park brake cable retaining bolt from the steering knuckle. Remove the steering knuckle from the vehicle.

3. To install, reverse removal procedure. Tighten all fasteners to specification. See TORQUE

NOTE: When lifting the vehicle DO NOT allow the jack to touch the rear steering gear. If the jack touches the rear steering gear you may damage the gear or the rack and pinion boots. If the boots are damaged replace the rack and pinion boot.

NOTE: Clean all of the sealing surfaces prior to installing the gasket. DO NOT reinstall the old gasket, replace the gasket whenever the actuator is removed from the axle. Install the steering gear actuator and gasket to the differential.



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SPECIFICATIONS . Lower vehicle.

Fig. 9: Separating Tie Rod End Courtesy of GENERAL MOTORS CORP.

PROPELLER SHAFT REPLACEMENT - ONE PIECE

Removal

CAUTION: Observe and accurately reference mark all driveline components relative



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1. Raise the vehicle. 2. Reference mark the propeller shaft to the rear axle pinion yoke. 3. Reference mark the propeller shaft to the transmission or transfer case. 4. Remove the bolts (1) and the yoke retainers (2) from the rear axle pinion yoke (3).

5. Slide the propeller shaft forward in order to disconnect the propeller shaft from the rear axle pinion yoke. 6. Slide the propeller shaft rearward in order to disconnect the propeller shaft from the transmission or

transfer case. 7. Remove the propeller shaft from the vehicle.

Installation

1. Inspect the splines of the slip yoke for a sufficient coating of grease. If the splines of the slip yoke does not have a sufficient coating of grease, lubricate the shaft with grease, GM P/N 12345879 or equivalent, RWD w/ Automatic Transmission Only.

2. Install the propeller shaft into the transmission or transfer case. Align the reference marks made during removal.

3. Install the propeller shaft (3) to the rear axle pinion yoke (4). Align the reference marks made during removal.

4. Install the yoke retainers (2) and bolts (1). Tighten to Specifications. 5. Lower the vehicle.

OVERHAUL

DIFFERENTIAL ASSEMBLY

to the propeller shaft and axles before disassembly. These components include the propeller shafts, the drive axles, the pinion flanges, the output shafts, etc. All components must be reassembled in the exact relationship to each other as they were when removed. In addition, published specifications and torque values, as well as any measurements made prior to disassembly must be followed.

NOTE: When removing the propeller shaft, do not attempt to remove the shaft by pounding on the yoke ears or using a tool between the yoke and the universal joint. If the propeller shaft is removed by using such means, the injection joints may fracture and lead to premature failure of the joint.

NOTE: Disassembly and overhaul procedures for differential case are not yet available from the manufacturer. Procedures are available for removal and installation of differential case and as an assembly. Removal and installation procedures are also available for ring gear and differential case side bearings. See DIFFERENTIAL CASE & RING GEAR under REMOVAL & INSTALLATION. Also



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ADJUSTMENTS

DRIVE PINION DEPTH

1. Assemble the pinion bearing installer bolt and bearing disc. Install outer pinion bearing onto the bearing installer and insert into the axle housing. Install the inner pinion bearing into the axle housing. Install the gauging plate onto inner pinion bearing and pinion bearing installer bolt. See Fig. 10 .

2. While holding the gauging plate stationary, tighten the nut on the installer bolt just until the end play between the pinion bearings is removed. Rotate the assembly several times in both directions in order to seat the pinion bearings.

3. Using an inch-pound torque wrench, measure the rotating torque of the assembly. The rotating torque of the assembly should be 20-45 INCH lbs. (2.3-5.1 N.m). If the rotating torque of the assembly is less than specification, continue to tighten the pinion bearing installer nut until specified rotating torque is obtained.

4. Assemble gauging discs and arbor and install into axle housing. Install dial indicator onto arbor. See Fig. 10 . Place the stem of the gauging discs, arbor and dial indicator assembly onto the bottom step of the pinion bearing installer.

5. Install the side bearing caps and side bearing cap bolts. Tighten the side bearing cap bolts to specification. See TORQUE SPECIFICATIONS . Rotate the gauging disc and arbor assembly. The arbor must rotate back and forth freely with the discs. If the assembly does not rotate freely, disassemble the components, inspect for proper seating and/or mis-aligned components and re-assemble.

6. Loosely clamp the dial indicator onto the stem on the gauging plate. Place dial indicator contact pad onto the mounting post of the arbor. Loosen the lock nut on the dial indicator and push down until the needle has turned 3/4 of a turn clockwise.

7. Tighten the dial indicator clamp finger tight. Move the plunger of the gauging discs, arbor and dial indicator assembly back and forth on the bottom step of the pinion bearing installer until the needle of the dial indicator indicates the greatest deflection. The deflection is the point where the needle changes direction. At the greatest point of deflection, move the indicator housing of the Dial Indicator (J-8001) until the needle indicates ZERO.

8. Move the plunger of the dial indicator back and forth again to verify the ZERO setting. Adjust the housing of the dial indicator as necessary to set the needle to ZERO. Rotate the arbor away from the gauging plate. The value indicated is the amount of pinion shim thickness required for a nominal pinion

see DIFFERENTIAL SIDE BEARINGS under REMOVAL & INSTALLATION.

NOTE: Pinion flange/yoke holder may also be referred to as pinion flange holder /remover.

NOTE: Drive pinion rear bearing shim thickness must be determined whenever a NEW axle housing, ring gear and pinion, or pinion bearings is installed.

NOTE: Corresponding letters are stamped on the bearing caps and axle housing. The bearing caps must be reassembled in the same position as removed.



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setting. 9. In order to adjust the pinion shim thickness for the drive pinion that is to be installed, read the number on

the button end of the pinion. If the number on the button end of the pinion is "0", no adjustment of the pinion preload shim pack is necessary. If the number is not "0", the number will also have a corresponding "+" or "-" in front of it. The "+" or "-" indicates the amount of pinion preload shim thickness that either needs to be added to or subtracted from the amount determined in step 8 in order to the drive pinion gear to be positioned properly within the axle housing. For example, go to next step.

10. For example, if the number on the button end of the pinion is a "+3", this indicates that 0.003" (0.0762 mm) of shim thickness will need to be subtracted from the value previously determined in step 8 in order to place the teeth of the pinion in the best running position with the teeth of the ring gear. If the number on the button end of the pinion is a "-3", this indicates that 0.003" (0.0762 mm) of shim thickness will need to be added to the value determined in step 8 in order to place the teeth of the pinion in the best running position with the teeth of the ring gear. Remove the pinion depth setting tools.

11. Remove the pinion bearings. Install the pinion position shim onto the drive pinion. Measure the thickness of the shim with a micrometer in order to verify the thickness. Install the inner pinion bearing onto the drive pinion using Bearing Installer (J-24433).

12. Install the original pinion preload shims onto the drive pinion. If the original shims are not available, assemble 0.060" (1.52 mm) of pinion preload shims to install. Measure each shim separately with a micrometer and add the thickness together to determine the total shim pack size. Install the drive pinion with the inner pinion bearing and the pinion preload shims into the axle housing.

13. Install the outer pinion bearing. Install the outer pinion bearing. Install the thrust washer. Seat the pinion yoke onto the pinion shaft by tapping it with a soft-faced hammer until a few pinion shaft threads show through the yoke.

14. Install the pinion yoke nut washer. Install the pinion yoke nut. Tighten the pinion yoke nut to 186 ft. lbs. (252 N.m). Measure the rotating torque of the drive pinion using an inch-pound torque wrench. Specification The rotating torque of the drive pinion should be between 20-45 INCH lbs. (2.3-5.1 N.m).

15. If the rotating torque of the drive pinion is not within specifications, adjust the pinion preload shim thickness by doing the following: Install the Pinion Flange/Yoke Holder (J-8614-01) to the pinion yoke. Remove the pinion nut while holding the pinion flange/yoke holder. Remove the washer.

16. Install pinion seal, pinion flange, washer and nut. Ensure pinion flange alignment mark is properly aligned with pinion shaft end mark. Using pinion flange/yoke holder, tighten pinion self-locking nut until all end play is removed. Rotate pinion several times to seat bearings. Check preload using an INCH-lb. torque wrench.

17. Continue tightening nut and checking preload until specified preload is obtained. See AXLE ASSEMBLY SPECIFICATIONS . DO NOT back off nut to lessen preload.

18. Remove the pinion yoke by turning pinion nut clockwise while holding the Pinion Flange Remover/Installer (J-8614-01). Apply a light coat of axle lubricant, GM P/N 12378557 or equivalent meeting GM Specification 9986207, to lip of the pinion seal. Install the NEW pinion oil seal using Seal Installer (J-45710).

19. Seat the pinion yoke onto the pinion shaft by tapping it with a soft-faced hammer until a few pinion shaft threads show through the yoke. Install the pinion yoke nut washer. Install the NEW pinion yoke nut. Tighten the pinion yoke nut to specification. See TORQUE SPECIFICATIONS .

20. Measure the rotating torque of the drive pinion using an INCH Lb. torque wrench. See Fig. 11 . See AXLE ASSEMBLY SPECIFICATIONS .



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Fig. 10: Cross-Sectional View Of Pinion Setting Gauge Set Courtesy of GENERAL MOTORS CORP.



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Fig. 11: Checking Drive Pinion Preload Courtesy of GENERAL MOTORS CORP.

SIDE BEARING PRELOAD

NOTE: Adjust drive pinion depth prior to performing side bearing preload adjustment. See DRIVE PINION DEPTH .



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1. Remove the differential side bearing shims. Determine the pinion position shim and the pinion preload shims, if necessary. Install the differential side bearing without the side bearing shims by doing the following:

A. In order to protect the differential case, install the Side Bearing Puller Pilot (J-36597) in the case on the side opposite of the bearing installation.

B. Install the differential side bearing. Install the Differential Side Bearing Installer (J-24430) and Universal Driver Handle (J-8092) over the differential side bearing.

C. Drive the differential side bearing into position using the differential side bearing installer and universal driver handle.

2. Install the differential assembly into the axle housing. Move the differential assembly to the left until the left differential side bearing is against the left side bearing bore.

3. Install the left side bearing cap. Install the left side bearing cap bolts. Tighten the bearing cap bolts finger tight. DO NOT torque the bolts to specification at this time.

4. While holding the differential assembly against the left side bearing bore, press the right side bearing race against the right differential side bearing.

5. Using a feeler gauge, measure the distance between the right side bearing race and the right side bearing bore. Use progressively larger feeler gauge sizes until a moderate drag is felt. Repeat this step several times while rotating the differential case in order to obtain a consistent reading. This measurement, measurement a, is the total shim pack thickness for the differential assembly without preload.

6. Remove the left side bearing cap bolts. Remove the left side bearing cap. Install the right side bearing cap. Install the right side bearing cap bolts. Tighten the bearing cap bolts finger tight. DO NOT torque the bolts to specification at this time. While holding the differential assembly ring gear against the drive pinion, press the left side bearing race against the left differential side bearing.

NOTE: Contact supplier for list of available shim sizes.

NOTE: Install the bearing caps into the same position from which each was removed.

NOTE: In order to accurately measure the differential side bearing shim thickness, the differential side bearing race must be evenly seated against the differential side bearing.

CAUTION: To prevent personal injury and/or component damage, support the differential case when removing the case from the axle housing. If the case is not supported, the differential case could fall and cause personal injury or damage to the differential case.

NOTE: In order to accurately measure the differential side bearing shim thickness, the differential side bearing race must be evenly seated against the differential side bearing.



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7. Using a feeler gauge, measure the distance between the left side bearing race and the left side bearing bore. Use progressively larger feeler gauge sizes until a moderate drag is felt. Repeat this step several times while re-positioning the differential case in order to obtain a consistent reading. This measurement is the left side shim thickness for the differential assembly without preload.

8. In order to determine the right side shim thickness, subtract the left side measurement from the total shim measurement. This measurement is the thickness for the right side shim thickness without preload or setting the initial backlash. Remove the right side bearing cap bolts. Remove the right side bearing cap. Remove the differential assembly.

9. Remove the differential side bearings. Install the Differential Side Bearing Remover (J-45711) and the side bearing puller pilot. Using a hydraulic press, remove the differential side bearings. Add 0.010" (0.25 mm) of shim thickness to the right side shim thickness measurement previously determined. This additional amount will set the differential side bearing preload and the initial backlash.

10. The number of shims required in order to equal the correct thickness may consist of one or more shims. Install the right side shim thickness onto the differential case. Measure the shims one at a time. Add the measurements together in order to obtain the total thickness of the right side shim pack.

11. Install the right differential side bearing with the side bearing shim. In order to protect the differential case, install the Side Bearing Protector (J-8107-3) in the case on the side opposite of the bearing installation. Place the differential side shim thickness on top of the differential case. Place the differential side bearing on top of the differential case.

12. Using procedure similar to right side bearing, install the left side bearing shim thickness and differential side bearing.

13. Install the differential assembly into the axle housing. See OVERHAUL . Adjust the backlash. See BACKLASH & FINAL ASSEMBLY under ADJUSTMENTS.

BACKLASH & FINAL ASSEMBLY

1. Determine the differential side bearing preload and initial backlash. See SIDE BEARING PRELOAD . See DRIVE PINION DEPTH . Install Guide Pins (J-25025) and Dial Indicator (J-8001) to the axle housing. See Fig. 12 .



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Fig. 12: Adjusting Ring Gear Backlash Courtesy of GENERAL MOTORS CORP.

2. Place the indicator stem of the dial indicator at the heel end of a gear tooth. Set the dial indicator so that the stem is aligned with the gear rotation and perpendicular to the tooth angle. While holding the pinion stationary, move the ring gear back and forth. Measure and record the backlash. Repeat the measuring procedure at eight points around the ring gear. The difference between the backlash at all of the measuring points should not vary by more than 0.002" (0.05 mm).

3. If the difference between the backlash at all of the measuring points varies by more than 0.002" (0.05 mm), inspect ring gear for burrs, a distorted case flange or uneven tightening of mounting bolts. Repair as necessary. If the difference between all the measuring points is 0.002" (0.05 mm) or less, go to next step.

4. The backlash at the minimum lash point measured between the ring gear and the drive pinion should be between 0.003-0.010" (0.08-0.25 mm) with a preferred backlash of 0.005-0.008" (0.13-0.20 mm). If adjustment is necessary, adjust the thickness of the shim pack on each side of the differential in equal amounts. This will maintain the correct axle side bearing preload.

5. If the backlash is not within specifications, adjust the backlash. Remove the differential side bearings. See OVERHAUL .

NOTE: Moving 0.002" (0.05 mm) of shim thickness from one side of the



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6. If the backlash is too small, increase the backlash. Remove the appropriate amount of thickness from the left side shim pack. For example, to increase the backlash by 0.004" (0.10 mm), subtract 0.008" (0.20 mm) of thickness from the left side shim pack. Add the 0.008" (0.20 mm) of shim thickness to the right side shim pack.

7. If the backlash is too large, decrease the backlash. Remove the appropriate amount of thickness from the right side shim pack. For example, to decrease the backlash by 0.004" (0.10 mm), subtract 0.008" (0.20 mm) of thickness from the right side shim pack. Add the 0.008" (0.20 mm) of shim thickness to the left side shim pack.

8. Install the left and right shim packs onto the differential case. Install the differential side bearings. See OVERHAUL . Recheck the backlash and adjust as necessary.

9. Once backlash is correct, perform a gear tooth contact pattern check in order to ensure proper alignment between the ring and pinion gears. See RIVE AXLE - GEAR TOOTH CONTACT PATTERNS in GENERAL INFORMATION.

AXLE ASSEMBLY SPECIFICATIONS

AXLE ASSEMBLY SPECIFICATIONS

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

differential to the other will change the backlash adjustment by 0.001" (0.03 mm).

Application SpecificationPinion Bearing Preload (1) 35-57 INCH Lbs. (3.9-6.4 N.m)Ring Gear Backlash .003-.010" (.08-.25 mm)Side Bearing Preload

New Bearings 20-45 INCH Lbs. (2.3-5.1 N.m)Used Bearings 10-25 INCH Lbs. (1.1-2.8 N.m)

(1) Preload measurement is torque needed to turn pinion in housing without differential case and ring gear installed.

Application Ft. Lbs. (N.m)Ball Joint Mounting Bolts 81 (110)Ball Joint Pinch Bolt (Lower) 169 (230)Differential Drain Plug 20 (27)Differential Fill Plug 15 (21)Drive Shaft Retainer Bolts 18 (24)Pinion Yoke Nut 273 (370)Ring Gear-To-Differential Case Bolt (1) 131 (178)Side Bearing Cap Bolt 80 (108)Steering Actuator/Differential Cover Bolts 45 (61)



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Steering Gear Shield Retaining Bolts 132 (180)Steering Gear Shield Retaining Bolts 40 (55)"U" Bolts 110 (150)Wheel Drive Shaft Retaining Nut 184 (250)Wheel Lug Nuts 140 (190)Yoke Retainer Bolts 18 (25)(1) Bolt is right-hand thread. Use NEW bolts.



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Axle Shafts - Rear 3500 Series

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