Chevrolet Silverado / GMC Sierra. Service manual — part 1400

CONSTANT NOISE

Checks

Action

Warped ring gear

Replace the ring gear. 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)

.

Loose differential case bolts Tighten differential case bolts to specifications. Refer to

Fastener Tightening Specifications.

Cause

Correction

DEFINITION: A noise heard in the rear axle during all driving conditions. This noise may
increase or decrease in volume based on different driving maneuvers and speeds.
Flat spot on the pinion or the
ring gear teeth

Replace the pinion and the ring gear. 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).

Flat spot on the pinion
bearing

Replace the bearing. Refer to Drive Pinion Bearings
Replacement (8.6, 9.5, 11.5 Inch Axle) or Drive Pinion
Bearings Replacement (10.5 Inch Axle).

Worn pinion splines

Replace the pinion. 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).

Low oil level

Fill the fluid level to specifications with the proper lubricant.
Refer to Rear Axle Lubricant Level Inspection (11.5 Inch
Axle) or Rear Axle Lubricant Level Inspection (8.6, 9.5
LD Axle) or Rear Axle Lubricant Level Inspection (10.5
Inch Axle).

Wrong or poor grade oil

Drain and refill the system with the proper lubricant. Refer to
Rear Axle Lubricant Replacement (8.6 Inch Axle) or
Rear Axle Lubricant Replacement (9.5 Inch LD Axle) or
Rear Axle Lubricant Replacement (10.5 Inch Axle).

Excessive pinion to ring gear
backlash

Adjust the pinion to ring gear backlash. Refer to Backlash
Adjustment (8.6 Inch Axle) or Backlash Adjustment
(10.5, 11.5 Inch Axles) or Backlash Adjustment (9.5 LD
Axle).

Adjust the pinion bearings preload. Refer to Pinion Depth

2008 Chevrolet Silverado 1500

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

Loose pinion bearings

Adjustment (10.5 Inch Axle) or Pinion Depth Adjustment
(8.6, 9.5/9.5LD, and 11.5 Inch Axles).

Excessive pinion end play

Adjust the pinion end play. Refer to Pinion Depth
Adjustment (10.5 Inch Axle) or Pinion Depth Adjustment
(8.6, 9.5/9.5LD, and 11.5 Inch Axles).

Incorrect differential
bearing preload

Adjust the differential bearing preload. Refer to Differential
Carrier Bearing Preload Adjustment (10.5 Inch, 11.5
Inch Axles) or

Differential Carrier Bearing Preload

Adjustment (8.6 Inch Axle)

or Differential Carrier

Bearing Preload Adjustment (9.5, and 9.5LD Inch Axles).

Incorrect backlash

Adjust the pinion and ring gear backlash. Refer to Backlash
Adjustment (8.6 Inch Axle) or Backlash Adjustment
(10.5, 11.5 Inch Axles) or Backlash Adjustment (9.5 LD
Axle).

Worn pinion bearings

Replace the pinion bearings. Refer to Drive Pinion Bearings
Replacement (8.6, 9.5, 11.5 Inch Axle) or Drive Pinion
Bearings Replacement (10.5 Inch Axle).

Worn differential bearings

Replace the differential bearings. Refer to Differential Side
Bearings Replacement (All Except 9.75 Inch Axle).

Worn pinion and ring gear

Replace the pinion and ring gear. 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).

Excessive ring gear runout

Replace the ring gear. 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).

Bent axle housing

Replace the axle housing. Refer to Rear Axle Housing
Replacement (w/Rear Drum) or Rear Axle Housing
Replacement (w/Rear Disc ).

Worn axle shaft dowel holes Replace the axle shaft. Refer to Rear Axle Shaft

Replacement (8.6 Inch Axle w/Drum Brake w/VSES) or
Rear Axle Shaft Replacement (8.6 Inch Axle w/Drum
Brakes w/o VSES) or Rear Axle Shaft Replacement (8.6,
9.5 Inch Axles w/VSES) or to Rear Axle Shaft and/or
Gasket Replacement.

Worn hub studs

Replace the wheel studs. Refer to Wheel Stud

2008 Chevrolet Silverado 1500

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

NOISY ON TURNS

WHEEL BEARING WEAR - REAR DRIVE AXLE (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)

Replacement .

Bent axle shaft

Replace the axle shaft. Refer to Rear Axle Shaft
Replacement (8.6 Inch Axle w/Drum Brake w/VSES) or
Rear Axle Shaft Replacement (8.6 Inch Axle w/Drum
Brakes w/o VSES) or Rear Axle Shaft Replacement (8.6,
9.5 Inch Axles w/VSES) or Rear Axle Shaft and/or Gasket
Replacement.

Checks

Action

Worn differential side gears
and pinions

Replace the differential side gears and pinions. Refer to
Differential Overhaul (11.5 Inch Axle) or Differential
Overhaul (9.5/9.5LD Inch Axles) or Differential Overhaul
(8.6 Inch Axle) or Differential Overhaul (10.5 Inch Axle).

Worn differential spider
gears

Replace the spider gears. Refer to Differential Overhaul
(11.5 Inch Axle) or Differential Overhaul (9.5/9.5LD Inch
Axles) or Differential Overhaul (8.6 Inch Axle) or
Differential Overhaul (10.5 Inch Axle).

Worn axle shaft splines

Replace the axle shaft. Refer to Rear Axle Shaft
Replacement (8.6 Inch Axle w/Drum Brake w/VSES) or
Rear Axle Shaft Replacement (8.6 Inch Axle w/Drum
Brakes w/o VSES) or Rear Axle Shaft Replacement (8.6,
9.5 Inch Axles w/VSES) or Rear Axle Shaft and/or Gasket
Replacement.

2008 Chevrolet Silverado 1500

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

Fig. 6: Identifying Minor Wear
Courtesy of GENERAL MOTORS CORP.

Light pattern on races and rollers can be caused by fine abrasives. Clean all of the parts including
the housings. Check the seals. Replace the bearings if rough or noisy. Replace the shaft if
damaged.

Wear (Major)

2008 Chevrolet Silverado 1500

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