Chevrolet Silverado / GMC Sierra. Service manual — part 1475

11. Install the J 8001 to the J 21777-1 as follows:

1. Loosely clamp the J 8001 onto the stem on the J 21777-1.

2. Place the contact pad of the J 8001 onto the mounting post of the J 21777-1.

3. With the contact pad of the J 8001 touching the mounting post of the J 21777-1,

loosen the lock nut on the J 8001 and push down on the J 8001 until the needle the J
8001 has turned 3/4 of a turn clockwise.

4. Tighten the clamp on the J 8001 finger tight.

12. Move the plunger of the J 21777-1 back and forth until the needle of the J 8001 indicates

the greatest deflection.

The deflection is the point where the needle changes direction.

Fig. 256: Measuring Necessary Shim Thickness
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

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

13. At the greatest point of deflection, move the housing of the J 8001 until the needle indicates

zero.

14. Move the plunger of the J 21777-1 back and forth again to verify the zero setting. Adjust the

housing of the J 8001 as necessary to set the needle to zero.

15. Rotate the plunger of the J 21777-1 away from the J 21777-29, 8.6 inch axle, the J 45108 ,

9. See Special Tools.5/9.5LD inch axles, or the J 44416-3, 11.5 inch axle, until it no longer
touches the J 21777-29, the J 45108 , or the J 44416-3. See Special Tools.

16. The value indicated on the J 8001 is the thickness of the shim needed in order to set the

depth of the pinion.

17. Select the shim that indicates the proper thickness. Measure the shim with a micrometer in

order to verify that the thickness is correct.

18. Remove the pinion depth setting tools.

19. Remove the pinion bearings.

20. Install the pinion shim between the pinion gear and the inner pinion bearing. Refer to Drive

Pinion Bearings Replacement (8.6, 9.5, 11.5 Inch Axle) or Drive Pinion Bearings
Replacement (10.5 Inch Axle).

DIFFERENTIAL CARRIER BEARING PRELOAD ADJUSTMENT (10.5 INCH, 11.5 INCH AXLES
AXLES)

Tools Required

J 24429 Side Bearing Backlash Spanner. See Special Tools.

Adjustment

1. Install the pinion gear bearing retainer (10.5 in axle) or the drive pinion. Refer to Drive

Pinion Housing and/or Seal Replacement.

IMPORTANT:

The differential side bearing preload is adjusted by the 2
adjusting nuts in the bearing bore. The bore and the bearing
cap provide the mating threads for the bearing nut.

The differential must be initially preloaded in order to
determine the backlash of the gear set. After the backlash is
set, the final bearing preload is set.

The rotating torque of the drive pinion must be within
specifications before the pinion gear bearing retainer can be
installed.

2008 Chevrolet Silverado 1500

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

2. Install the drive pinion (11.5 in axle). Refer to Drive Pinion and Ring Gear Replacement

(8.6, 9.5/9.5LD, and 11.5 Inch Axles) or Drive Pinion and Ring Gear Replacement
(10.5 Inch Axle).

3. Install the differential side bearings, if necessary. Refer to Differential Side Bearings

Replacement (All Except 9.75 Inch Axle).

4. Install the differential side bearing adjuster nuts.

5. Install the differential case assembly.

If the differential case assembly cannot be installed, turn the differential side bearing
adjuster nuts into the axle housing until the differential case assembly can be installed.

6. Install the differential bearing caps.

7. Install the differential bearing cap bolts.

Tighten the bearing cap bolt finger-tight. Do not torque the bearing cap bolts at this time.

8. Slide the differential case assembly towards the right side axle housing until the ring gear

contact the pinion.

This is the zero backlash point.

If the zero backlash cannot be obtained, turn the right side differential bearing adjuster nut
in towards the axle housing until the ring gear fully contacts the pinion to obtain the zero
backlash.

9. While holding the ring gear against the pinion, turn the left differential bearing adjuster nut

out from the axle housing using the J 24429 until it contacts the differential side bearing.

IMPORTANT: The rotating torque of the drive pinion must be within

specifications before installing the differential case
assembly.

IMPORTANT: Before installation of the differential case assembly, ensure

that the side bearing surfaces in the carrier are clean and
free of burrs. If the original bearings are to be reused, the
original bearing cups must also be used.

IMPORTANT: Do not force the ring gear into contact with the drive pinion.

2008 Chevrolet Silverado 1500

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

See Special Tools.

10. Turn the right differential bearing adjuster nut out from the axle housing using the J 24429

until it contacts the differential side bearing. See Special Tools.

11. Back off the left adjusting nut approximately 2 slots using the J 24429 in order to obtain the

initial backlash adjustment. See Special Tools.

12. Install the left adjuster nut lock and the adjuster nut lock bolt.

Do not torque the bolt at this time.

13. Firmly tighten the right differential bearing adjuster nut using the J 24429 in order to force

the differential case assembly into solid contact with the left differential adjuster nut. See
Special Tools.

14. Rotate the pinion several times in order to seat the bearings.

15. Loosen the right differential bearing adjuster nut using the J 24429 until the nut is free from

the differential side bearing. See Special Tools.

16. Tighten the right differential bearing adjuster nut using the J 24429 until the differential

bearing adjuster nut contacts the bearing. See Special Tools.

17. 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.

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.

18. Install the right differential bearing adjuster nut lock.

19. Install the right differential bearing adjuster nut lock bolt.

Do not torque the bolt at this time.

20. Tighten the bearing cap bolts.

Tighten:

For the 10.5 in axle, tighten the bearing cap bolts to 185 N.m (136 lb ft).

For the 11.5 in axle, tighten the bearing cap bolts to 207 N.m (153 lb ft).

NOTE:

Refer to Fastener Notice .

2008 Chevrolet Silverado 1500

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