Chevrolet Silverado / GMC Sierra. Service manual — part 1384

Fig. 218: Removing Left Side Differential Bearing Adjuster
Courtesy of GENERAL MOTORS CORP.

32. Turn the left side differential adjuster nut clockwise using the J 36615 in order to preload

the differential side bearings against the differential side bearing cups. See Special Tools.

Tighten: Tighten the differential adjuster nut to 75 N.m (55 lb ft).

33. Rotate the pinion several times in order to seat the pinion and differential side bearings.

34. Measure the rotating torque of the drive pinion and differential assembly using an inch-

pound torque wrench.

2008 Chevrolet Silverado 1500

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

Specification: The rotating torque of the pinion and differential assembly should be 3.4-6.2
N.m (30-55 lb in) for new bearings or 2.8-5.1 N.m (25-45 lb in) for used bearings.

Fig. 219: Alignment Mark Between Differential Adjuster Nut Sleeve & Differential
Carrier Case
Courtesy of GENERAL MOTORS CORP.

35. If the rotating torque measurement is below 2.8 N.m (25 lb in) for used bearings, or 3.4 N.m

(30 lb in) for new bearings, adjust the differential side bearing preload using the following
steps:

1. Place an alignment mark between the differential adjuster nut sleeve and the

differential carrier case, left and right sides.

2. Using the J 36599-A or the J 36615 , turn the left and the right side differential

adjuster nut sleeves in or clockwise one notch. See Special Tools.

3. Measure the rotating torque of the pinion and differential assembly using an inch-

2008 Chevrolet Silverado 1500

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

pound torque wrench.

4. Compare the new measurement to the specification listed in step 34. If the rotating

torque of the pinion and differential assembly is not within specifications, continue to
tighten the left and right side differential adjuster nut sleeves one notch at a time on
each side until the rotating torque of the pinion and differential assembly is within
specifications.

36. If the rotating torque measurement is above 5.1 N.m (45 lb in) for used bearings, or 6.2 N.m

(55 lb in) for new bearings, adjust the differential side bearing preload using the following
steps:

1. Place an alignment mark between the differential adjuster nut sleeve and the

differential carrier case, left and right sides.

2. Using the J 36599-A or the J 36615 , turn the left and the right side differential

adjuster nut sleeves out or counterclockwise one notch. See Special Tools.

3. Measure the rotating torque of the pinion and differential assembly using an inch-

pound torque wrench.

4. Compare the new measurement to the specification listed in step 34. If the rotating

torque of the pinion and differential assembly is not within specifications, continue to
loosen the left and right side differential adjuster nut sleeves one notch at a time on
each side until the rotating torque of the pinion and differential assembly is within
specifications.

37. Once the specified rotating torque is obtained, rotate the pinion several times to ensure the

bearings have seated.

Recheck the rotating torque and adjust if necessary.

38. Measure the drive pinion to ring gear backlash and adjust, if necessary. Refer to Backlash

Inspection and Adjustment.

39. Once the bearing preload and drive pinion to ring gear backlash is within specifications,

perform a gear tooth contact pattern check to ensure proper contact between the pinion and
the ring gear. Refer to Gear Tooth Contact Pattern Inspection.

40. Complete the assembly of the differential carrier. Refer to Differential Carrier Assembly

Final Assembly (8.25 F4WD Axle) or Differential Carrier Assembly Final Assembly
(8.25 S4WD and 9.25 Axles).

BACKLASH INSPECTION AND ADJUSTMENT

Tools Required

2008 Chevrolet Silverado 1500

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

J 8001 Dial Indicator Set

J 36599-A Side Bearing Nut Wrench. See Special Tools.

J 36615 Side Bearing Nut Wrench. See Special Tools.

Inspection and Adjustment

1. Remove all alignment marks made previously and re-mark the location of the differential

adjuster nut sleeves in relation to the differential carrier assembly case halves.

Ensure that the notches can be counted when turned.

2008 Chevrolet Silverado 1500

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