Noise Acceptability
A gear driven unit will produce a certain amount of noise. Some noise is acceptable and audible at certain speeds, or under various driving conditions, such as a newly-paved blacktop road. Slight noise is not detrimental to the operation of the axle and is considered normal.
Intermittent Noise
| Cause | Correction |
|---|---|
| Inspect for proper gear oil levels prior to performing system diagnosis. | |
| Low gear oil levels | Fill axle to the recommended level. Refer to REAR AXLE LUBRICANT REPLACEMENT . A low level may create intermittent or incomplete clutch park engagement. |
| Incorrect gear oil | Replace with gear oil, GM P/N 12378514 (Canadian P/N 88901045). Refer to REAR AXLE LUBRICANT REPLACEMENT . Incorrect gear oil may create improper clutch pack engagement or a slippage condition. |
| Worn clutch pack oil pump | Replace the clutch pack assembly. |
| Worn clutch pack friction discs | Replace the clutch pack assembly. |
INTERMITTENT NOISE CAUSE
Constant Noise
| Cause | Correction |
|---|---|
| Inspect for proper gear oil levels prior to performing system diagnosis. | |
| Low gear oil levels | Faulty oil seal or other types of leaks may contribute to lower than required fluid levels. Refer to REAR AXLE LUBRICANT LEAK DIAGNOSIS . Fill to the proper level with gear oil, GM P/N 12378514 (Canadian P/N 88901045). Refer to REAR AXLE LUBRICANT REPLACEMENT . |
| Worn or loose axle mounts | Repair or replace axle mounts as required. Refer to DIFFERENTIAL HOUSING SUPPORT BUSHING REPLACEMENT (FRONT) and DIFFERENTIAL HOUSING SUPPORT BUSHING REPLACEMENT (REAR) . |
| Worn propeller shaft constant velocity or universal joints | Replace the universal joints as required. Refer to PROPELLER SHAFT REPLACEMENT . If constant velocity joint is damaged, replace the propeller shaft. Refer to PROPELLER SHAFT REPLACEMENT . |
| Worn propeller shaft center bearing assembly | Replace the center bearing assembly. Refer to PROPELLER SHAFT REPLACEMENT . |
| Bearing noise within axle assembly | This type of noise will decrease or increase relative to the vehicle speed. Check for the proper fluid level. Refer to REAR AXLE LUBRICANT REPLACEMENT . Repair or replace the unit as required. |
| Gear set whine noise within the carrier assembly caused by incorrect backlash | A whine type of noise will increase or decrease relative to the vehicle speed. Check for the proper fluid level. Refer to REAR AXLE LUBRICANT REPLACEMENT . Repair or replace the unit as required. |
CONSTANT NOISE CAUSE