Chevrolet Silverado / GMC Sierra. Manual — part 1483

Specification: The difference between the backlash at all of the measuring points should
not vary by more than 0.05 mm (0.002 in).

11. If the difference between the backlash at all of the measuring points varies by more than

0.05 mm (0.002 in), inspect for the following conditions:

Burrs

A distorted case flange

Uneven bolting

12. If the difference between all the measuring points is within specifications, the backlash at

the minimum lash point measured should be:

Specification: The backlash between the ring gear and the drive pinion should be between
0.08-0.25 mm (0.003-0.010 in) with a preferred backlash of 0.13-0.18 mm (0.005-0.007
in).

13. If the backlash is not within specifications, adjust the backlash by performing the following

procedure:

1. Remove the differential bearing adjuster nut retainer bolt.

2. Remove the differential bearing adjuster nut retainer.

3. Loosen the bearing cap bolts.

14. Do not remove the bearing cap bolts.

1. Loosen the differential bearing adjuster nut using the J 24429 . See Special Tools.

2. Remove the differential side bearing shim.

3. Measure the thickness of the shim.

15. Calculate the average of the 3 measurements.

16. Record the measurement.

If the backlash is too small, select a smaller shim than the one that was removed. For
example, to increase the backlash by 0.05 mm (0.002 in), select a shim that is 0.10 mm
(0.004 in) thinner than the shim that was removed.

If the backlash is too large, select a larger shim than the one that was removed. For
example, to increase the backlash by 0.05 mm (0.002 in), select a shim that is 0.10 mm
(0.004 in) thicker than the shim that was removed.

IMPORTANT: Increasing or decreasing the shim thickness by 0.05 mm

(0.002 in) will change the backlash adjustment approximately
0.03 mm (0.001 in).

2008 Chevrolet Silverado 1500

2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Install the shim.

17. Tighten the differential bearing adjuster nut using the J 24429 until the differential bearing

adjuster nut is seated against the bearing cup. See Special Tools.

18. Once the differential bearing adjuster is seated against the differential bearing, tighten the

differential bearing adjuster nut using the J 24429 the following additional amounts:. See
Special Tools.

Tighten:

For used bearings, tighten the differential bearing adjuster nut an additional 2 slots.

For new bearings, tighten the differential bearing adjuster nut an additional 3 slots.

19. Tighten the differential bearing cap bolts.

Tighten: Tighten the bearing cap bolts to 85 N.m (63 lb ft).

20. Recheck the backlash following the steps above to verify that the backlash is within

specifications.

21. Install the differential bearing adjuster nut retainer.

22. Install the differential bearing adjuster nut retainer bolt.

Tighten: Tighten the differential bearing adjuster nut retainer nut bolt to 26 N.m (19 lb ft).

23. Measure the drive pinion and differential case side bearing preload and adjust, if necessary

following the steps above.

24. Once the backlash and bearing preload is correct, perform a gear tooth contact pattern

check in order to ensure proper alignment between the ring and pinion gears. Refer to Gear
Tooth Contact Pattern Inspection.

GEAR TOOTH CONTACT PATTERN INSPECTION

Pattern Evaluation (Ring Gear)

NOTE:

Refer to Fastener Notice .

Drive Side

Coast Side

Pattern

Condition

Corrective Action

Heel Toe

Toe Heel

2008 Chevrolet Silverado 1500

2008 Driveline/Axle Rear Drive Axle - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado