Chevrolet Silverado / GMC Sierra. Service manual — part 1320

Worn thrust washers

Excessive clearance between the side gears and the axle shafts

Excessive clearance between differential side gears and the bore in the case

Excessive drive pinon and ring gear backlash

Inspect, adjust or replace the affected components as necessary.

NOISY IN DRIVE

Checks

Action

Excessive pinion to ring
gear backlash

Adjust the pinion to ring gear backlash. Refer to Backlash
Inspection and Adjustment.

Worn pinion and ring gear

Replace the pinion and the ring gear. Perform the following
procedures:

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2. Differential Case Assembly Disassemble (8.25 Inch

Axle) or Differential Case Assembly Disassemble
(9.25 Inch Axle)

3. Differential Case Assembly Assemble (8.25 Inch

Axle) or Differential Case Assembly Assemble (9.25
Inch Axle)

4. Front Differential Drive Pinion Gear Bearing Cup

Installation (9.25 Inch Axle w/J 45754) or Front
Differential Drive Pinion Gear Bearing Cup
Installation (8.25 Inch Axle w/J 45858) or Front
Differential Drive Pinion Gear Bearing Cup
Installation (8.25/9.25 Inch Axles w/J 36598)

5. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

Worn pinion bearings

Replace the pinion bearings. Perform the following
procedures:

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2008 Chevrolet Silverado 1500

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

2. Front Differential Drive Pinion Gear Bearing Cup

Installation (9.25 Inch Axle w/J 45754) or Front
Differential Drive Pinion Gear Bearing Cup
Installation (8.25 Inch Axle w/J 45858) or Front
Differential Drive Pinion Gear Bearing Cup
Installation (8.25/9.25 Inch Axles w/J 36598)

3. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

Loose pinion bearings

Adjust the pinion bearings preload. Perform the following
procedures:

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

3. Backlash Inspection and Adjustment

Excessive pinion end play

Adjust the pinion end play. Refer to Differential Carrier
Assembly Assemble (8.25 Inch Axle Lock Ring Style) or

Differential Carrier Assembly Assemble (9.25 Inch Axle)

.

Worn differential bearings

Replace the differential bearings. Perform the following
procedures:

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2. Differential Case Assembly Disassemble (8.25 Inch

Axle) or Differential Case Assembly Disassemble
(9.25 Inch Axle)

3. Differential Case Assembly Assemble (8.25 Inch

Axle) or Differential Case Assembly Assemble (9.25
Inch Axle)

4. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

Loose differential bearings

Adjust the differential bearing preload. Perform the following
procedures:

2008 Chevrolet Silverado 1500

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

NOISY WHEN COASTING

INTERMITTENT NOISE

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

Excessive ring gear runout

Replace the ring gear. Perform the following procedures:

1. Differential Carrier Assembly Disassemble (9.25

Inch Axle)

2. Differential Carrier Assembly Assemble (8.25 Inch

Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle)

Low oil level

Fill the fluid level to specifications with the proper lubricant.
Refer to Front Axle Lubricant Level Inspection (9.25 Inch
Axle).

Wrong or poor grade oil

Drain and refill the system with the proper lubricant. Refer to
Front Axle Lubricant Replacement.

Checks

Action

DEFINITION: Noise is audible when slowing down and disappears when driving.
Worn pinion and ring gear

Adjust or replace the pinion and the ring gear. Refer to
Differential Carrier Assembly Disassemble (9.25 Inch
Axle).

Pinion and ring gear too
tight

Adjust the pinion and the ring gear backlash. Refer to
Backlash Inspection and Adjustment.

Checks

Action

Warped ring gear

Replace the ring gear. Refer to Differential Carrier
Assembly Disassemble (9.25 Inch Axle).

Loose differential case
assembly

Set the differential case assembly to the proper preload and
backlash. Refer to Differential Carrier Assembly Assemble
(8.25 Inch Axle Lock Ring Style) or Differential Carrier
Assembly Assemble (9.25 Inch Axle) and Backlash

2008 Chevrolet Silverado 1500

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

CONSTANT NOISE

NOISY ON TURNS

FRONT DRIVE AXLE BEARING WEAR (STRAIGHT)

Straight Roller Bearing Diagnosis

Consider the following factors when diagnosing a bearing condition:

Note the general condition of all parts during disassembly and inspection.

Classify the failure with the aid of the illustrations.

Determine the cause.

Make all repairs following recommended procedures.

Wear (Minor)

Inspection and Adjustment.

Checks

Action

Flat spot on the pinion or
the ring gear teeth

Replace the pinion and the ring gear. Refer to Differential
Carrier Assembly Disassemble (9.25 Inch Axle).

Flat spot on the pinion
bearing

Replace the bearing. Refer to Differential Carrier Assembly
Disassemble (9.25 Inch Axle).

Worn pinion splines

Replace the pinion. Refer to Differential Carrier Assembly
Disassemble (9.25 Inch Axle).

Checks

Action

Worn differential side gears
and pinions

Replace the differential side gears and pinions. Refer to
Differential Case Assembly Disassemble (8.25 Inch Axle)
or

Differential Case Assembly Disassemble (9.25 Inch

Axle)

.

Worn differential spider

Replace the spine gears. Refer to Differential Case
Assembly Disassemble (8.25 Inch Axle) or Differential
Case Assembly Disassemble (9.25 Inch Axle).

Worn axle shaft splines

Replace the axle shaft. Refer to Front Drive Axle Inner
Shaft and Inner Shaft Housing Replacement (8.25 F4WD
Axle) or Front Drive Axle Inner Shaft and Inner Shaft
Housing Replacement (8.25 S4WD and 9.25 Axles).

2008 Chevrolet Silverado 1500

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