GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Inspect for the proper gear oil levels prior to performing system diagnosis. Refer to Lubricant Change .

Incorrect type fluid

Installation of the incorrect type gear oil may create a "moan" type noise within 7 770-25 900 km (3-10,000 miles). Fluid that is "black" in color is to be considered normal and is darkened by the carbon material in the clutch plates.

Replace the rear differential assembly as required.

Fluid replacement will not correct a "moan" condition caused by the use of incorrect oil. Refer to Differential Replacement .

Water or contamination within the transmission oil

Water or contamination within the transmission fluid, causing excessive torque converter clutch slip rate, may create a "grind, growl, or moan" in the rear differential or torque tube under light or steady load conditions.

Replace the transmission fluid and flush the transfer case of the contaminated fluid. Refer to Internal Components Cleaning and Inspection in Transfer Case - Steyr.

Loose propeller shaft mounting bolts

Tighten the bolts as required. Refer to Propeller Shaft Replacement in Propeller Shaft.

Worn propeller shaft constant velocity joints

Replace propeller shaft assembly. Refer to Propeller Shaft Replacement in Propeller Shaft.

Worn axle shaft constant velocity joints

Replace the constant velocity joints as required.

Worn, loose, or missing differential mounts

Repair or replace the differential mounts as required.

Loose torque tube bracket or a worn bracket bushing

Tighten the bracket bolts or replace the bracket as required.

Worn bearing in the torque tube assembly

Replace the torque tube assembly

Torque tube dampner loose or missing

A "moan" or "exhaust leak" type noise at higher engine speeds, approximately 2,000-2,500 RPM, may indicate a loose or missing dampner.

Tighten the dampner retaining bolt or replace the torque tube assembly as required.

Bearing noise within the differential assembly

A "grinding" or "roar" type noise will increase or decrease relative to the vehicle speed.

  1. Check for the proper fluid level. Fill as required.
  2. If the noise continues, replace unit as required.

Gear set "whine" noise within the differential assembly

A "whine" type noise will increase or decrease relative to the vehicle speed approximately 80-97 km/h (50-60 mph).

  1. Check for the proper fluid level. Fill as required.
  2. Replace unit as required.