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Differential Case



Note: This article has been revised in accordance with GM TSB#05-04-20-002, dated May 13, 2005.


Standard Rear Axle Assembly:







Rear Axle Assembly With Traction Control (Acceleration Slip Regulation):









^ Tools Required:
- J 22888-20A Differential Side Bearing Remover
- J 8107-2 Differential Side Bearing Remover Plug
- J 8092 Driver Handle
- J 21465-13 Driver Handle Extension
- J 25299 Differential Side Bearing Installer
- J 25588 Side Bearing:Shim Installer
- J 39446 ABS Exciter Ring Protector Kit

REMOVE OR DISCONNECT





Important:
- Before removing the differential case (33) from the rear axle housing (16), differential ring gear-to-differential drive pinion gear backlash must be checked. This will indicate gear or bearing wear or an error in backlash or preload setting which will help in determining the cause of axle noise.

1. Rear axle shafts.
2. Sensor plug mounting bolt/screw (73) from wheel speed sensor (75) on vehicles with standard non-traction control rear axles only.
3. Wheel speed sensor (75) on vehicles with standard non-traction control rear axles.
- Carefully place wheel speed sensor (75) along side of rear axle housing (16).
4. Differential carrier bearing cap bolts/screws (26).

Important:
a. Differential carrier bearing caps (22) should be marked "R" and "L" to make sure they will be reassembled in their original locations.
b. Place right and left bearing outer races of differential (side) bearings (32) and bearing shims (24) in sets with marked carrier bearing caps (22) so that they can be reinstalled in their original positions.

5. Differential bearing shims (24).

NOTICE:
- Be careful when prying the differential case out of the axle housing to prevent damage of the cover gasket surface.
- Support the differential case during removal to prevent case from falling and being damaged.

6. Differential case (33) from rear axle housing (16).

Disassemble





1. Differential (side) bearing (32) from differential case (33), if replacing, using J 22888-20 and J 81072. If removing an Auburn type limited slip differential case, skip step 2.

Note: When removing the side differential case bearings, you may discover that recommended tool J 22888-20 does not work because some limited-slip differential cases do not have notches for the jaws of the puller. Use tool J 34168 to press the bearing off the case.

2. Upper and lower pinion gears, pinion thrust washers (37), left and right pinion gears and differential side gear thrust washers (38) from differential case (33).
- Mark pinion gears (40) and differential case (33) so pinion gears (40) can be reinstalled in their original position.
3. All ring gear bolts/screws (28) from differential case (33), if replacing ring gear (20) or speed sensor reluctor wheel (39).
- Differential ring gear bolts/screws (28) are left-hand thread type.
- Discard ring gear bolts/screws (28).
4. Ring gear (20) from differential case (33).
- Do not pry between ring gear (20), speed sensor reluctor wheel (39) and differential case (33), if ring gear (20) is on tight.
- Drive ring gear (20) from differential case (33) using brass drift and hammer.

Important: Speed sensor reluctor wheel must be replaced if removed from vehicles with standard rear axles.

5. Speed sensor reluctor wheel (39) only if necessary, using brass hammer.
- Discard speed sensor reluctor wheel (39).

Assemble

NOTICE: Always use the correct fastener in the correct location. When you replace a fastener, use ONLY the exact part number for that application. The Manufacturer will call out those fasteners that require a replacement after removal. The Manufacturer will also call out the fasteners that require thread lockers or thread sealant. UNLESS OTHER WISE SPECIFIED, do not use supplemental coatings (paints, greases, or other corrosion inhibitors) on the threaded fasteners or fastener joint interfaces. Generally, such coatings adversely affect the fastener torque and the joint clamping force, and may damage the fastener. When you install fasteners, use the correct tightening sequence and specifications. Following these instructions can help you avoid damage to parts and systems.

Important:
- Before reassembling the differential, lubricate all parts with axle lubricant or SAE 80W-90 GL-5 gear lubricant or equivalent.

Clean
- Connecting surfaces of ring gear (20) and differential case (33), if replacing ring gear (20).

CAUTION: Once the speed sensor reluctor wheel has been removed from. the differential case, a new speed sensor. reluctor wheel must be installed. The press fit may be lost if the speed sensor reluctor wheel Is used more than once. This would allow the speed sensor reluctor wheel to rotate freely on the differential case causing a significant reduction In performance of the antilock brake system, which could result in bodily injury.





1. Speed sensor reluctor wheel (39), if removed from vehicles with non-traction control rear axles.
- Carefully place speed sensor reluctor wheel (39) over differential case (33) on ring gear side.
2. Ring gear (20), if removed.
- On vehicles with standard rear axles, position ring gear (20) over speed sensor reluctor wheel (39).
3. Two ring gear bolts/screws (28) into opposite sides of ring gear (20). If converting to an Auburn type limited slip differential case, skip to step 4.
- Install remaining new ring gear bolts/screws (28) until just snug.

Tighten
- Differential ring gear bolts/screws (28) alternately in progressive stages to 120 Nm (89 ft. lbs.).

4. Side gear thrust washers (38), pinion gears (40), and pinion thrust washers (37) into differential case (33).
a. Position side gear thrust washers (38) over side gear hubs and install pinion gears (40) in differential case (33). If same parts are reused, install in original sides.
b. Position one upper or lower pinion gear, without pinion thrust washer (37), between left and right pinion gears and rotate pinion gears until upper or lower pinion gear is directly opposite loading opening in differential case (33). Place other pinion gear between left and right pinion side gears so that pinion gear shaft holes are in line: then rotate gears, lining up holes in upper and lower pinion gears with holes in differential case (33).
c. Rotate upper and lower pinion gears back toward loading opening just enough to permit sliding in pinion thrust washers (37).





5. Differential bearings (32) to differential case (33), if removed, using J 8092, J 25299 and J 21465-13.

INSTALL OR CONNECT

NOTICE: Always use the correct fastener in the correct location. When you replace a fastener, use ONLY the exact part number for that application. The Manufacturer will call out those fasteners that require a replacement after removal. The Manufacturer will also call out the fasteners that require thread lockers or thread sealant. UNLESS OTHER WISE SPECIFIED, do not use supplemental coatings (paints, greases, or other corrosion inhibitors) on the threaded fasteners or fastener joint interfaces. Generally, such coatings adversely affect the fastener torque and the joint clamping force, and may damage the fastener. When you install fasteners, use the correct tightening sequence and specifications. Following these instructions can help you avoid damage to parts and systems.

1. Differential case (33) into rear axle housing (16).





2. Differential bearing shims (24).

Important:
- Do not attempt to reinstall the production bearing shims as they may break when tapped into place.
- If service bearing shims were previously installed, they can be reused, but whether using new or old differential bearings (32), adhere to the following procedure in all cases. If differential bearings (32) are used again, they must have original outer races in place. Refer to "DIFFERENTIAL BEARING PRELOAD ADJUSTMENT."
- Keep bearing shim Packs in their respective position, right or led side.

a. Select a bearing shim 0.10 mm (0.004 inch) thicker than the one removed from the left side, then insert left side bearing shim pack between the spacer and the left bearing race.
b. Loosely install carrier bearing cap (22).
c. Select a bearing shim 0.10 mm (0.004 inch) thicker than the one removed from the right side and insert between the spacer (25) and the right bearing race.
d. It will be necessary to drive the right bearing shim into position using J 25588.

3. Differential bearing cap bolts/screws (26).
- Tighten Differential carrier bearing cap bolts/screws (26) to 75 Nm (55 ft. lbs.).
4. Check backlash and correct if necessary. Refer to "DIFFERENTIAL RING GEAR-TO-DIFFERENTIAL DRIVE PINION GEAR BACKLASH."
5. Rear axle shafts (63 or 70).
6. Wheel speed sensor (753 and sensor plug mounting bolt/screw (73), if removed.
- Tighten Wheel speed sensor mounting plug bolt/screw (73) to 10 Nm (89 inch lbs.).
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