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Chevrolet Silverado / GMC Sierra. Manual - part 1478
If the ZERO backlash cannot be obtained, turn the differential bearing adjuster nut into the
axle housing using the J 24429 until the ring gear fully contacts the drive pinion to obtain
the ZERO backlash. See Special Tools.
8. While holding the ring gear against the pinion, turn the differential bearing adjuster nut out
from the axle housing using the J 24429 until it contacts the differential side bearing. See
Special Tools.
9. Turn the adjuster nut out from the axle housing an additional 2 slots using the J 24429 in
order to obtain the initial backlash adjustment. See Special Tools.
10. Install the adjuster nut lock and the adjuster nut lock bolt.
11. Remove the left side differential bearing cap bolts.
12. Remove the left side differential bearing cap.
Fig. 257: J 22779
Courtesy of GENERAL MOTORS CORP.
13. Install the J 22779 into the left side axle housing between the differential bearing bore and
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
the differential bearing cup. See Special Tools.
14. Tighten the knob of the J 22779 until there is moderate drag when the J 22779 is moved.
See Special Tools.
15. Remove the J 22779 . See Special Tools.
16. Measure the J 22779 in 3 locations. See Special Tools.
17. Calculate the average of the 3 measurements.
The resulting value is the shim thickness required in order to set the initial backlash of the
differential assembly.
18. Select a service shim of approximately the same thickness to install into the axle housing.
Verify the thickness of the service shim using a micrometer.
19. Install the service shim into the axle housing between the differential bearing bore and the
differential bearing cup.
20. Install the left side differential bearing cap.
21. Install the left side differential bearing cap bolts.
Tighten the differential bearing cap bolts finger-tight. Do not torque the bolts at this time.
22. Remove the differential bearing adjuster nut lock bolt.
23. Remove the differential bearing adjuster nut lock.
24. Firmly tighten the differential bearing adjuster nut using the J 24429 in order to force the
differential case assembly into solid contact with the service shim. See Special Tools.
25. Rotate the pinion several times in order to seat the bearings.
26. Loosen the differential bearing adjuster nut using the J 24429 until the nut is free from the
differential side bearing. See Special Tools.
27. Tighten the differential bearing adjuster nut using the J 24429 until the differential bearing
adjuster nut contacts the bearing. See Special Tools.
28. Once the right differential bearing adjuster contacts the differential bearing, tighten the
differential bearing adjuster nut using the J 24429 the following additional amounts:. See
Special Tools.
IMPORTANT: Over-tightening may spread the axle housing and result in
incorrect shim selection.
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Tighten:
For new bearings, tighten the differential bearing adjuster nut an additional 3 slots.
For used bearings, tighten the differential bearing adjuster nut an additional 2 slots.
29. Install the right differential bearing adjuster nut lock.
30. Install the right differential bearing adjuster nut lock bolt.
Do not torque the bolt at this time.
31. Tighten the bearing cap bolts.
Tighten: Tighten the bearing cap bolts to 85 N.m (63 lb ft).
32. Tighten the differential bearing adjuster nut lock bolt.
Tighten: Tighten the differential bearing adjuster nut lock bolt to 26 N.m(19 lb ft).
33. Measure the drive pinion and differential case side bearing preload using an inch-pound
torque wrench.
Rotate the pinion several times to ensure the bearings have seated.
Specification: The rotating torque of the drive pinion and differential case bearings should
be 0.57-1.13 N.m (5-10 lb in) greater than the rotating torque of the drive pinion measured
earlier.
Record the measurement.
34. Calculate the differential side bearing preload by subtracting the drive pinion preload,
measured in Step 2, from the drive pinion and differential case bearing preload, measured in
Step 33.
Multiply the value obtained by the axle ratio.
Specification: The differential case side bearing preload should be 1.7-4.0 N.m (15-35 lb
in).
35. If the differential case side bearing preload is not within specifications, use the J 24429 and
turn the differential side bearing adjuster nut in or out one slot at a time in order to
NOTE:
Refer to Fastener Notice .
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
increase/decrease the side bearing preload.
36. Once the differential side bearing preload is correct, measure the drive pinion to differential
assembly backlash and adjust, if necessary. Refer to Backlash Adjustment (8.6 Inch Axle)
or Backlash Adjustment (10.5, 11.5 Inch Axles) or Backlash Adjustment (9.5 LD
Axle).
Differential side bearing shims are available in the following sizes:
Shim Sizes:
5.59 mm (0.220 in)
5.64 mm (0.222 in)
5.69 mm (0.224 in)
5.74 mm (0.226 in)
5.79 mm (0.228 in)
5.84 mm (0.230 in)
5.89 mm (0.232 in)
5.94 mm (0.234 in)
5.99 mm (0.236 in)
6.05 mm (0.238 in)
6.10 mm (0.240 in)
6.15 mm (0.242 in)
6.20 mm (0.244 in)
6.25 mm (0.246 in)
6.30 mm (0.248 in)
6.35 mm (0.250 in)
6.40 mm (0.252 in)
6.45 mm (0.254 in)
6.50 mm (0.256 in)
6.55 mm (0.258 in)
WHEEL BEARING ADJUSTMENT
Preliminary Inspection
IMPORTANT: Ensure the brakes are fully released and do not drag.
2008 Chevrolet Silverado 1500
2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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