GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

Inspect for the proper transaxle and gear oil levels prior to performing system diagnosis. Refer to Transfer Case Fluid Drain and Fill .

Loose propeller shaft mounting bolts

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

Worn propeller shaft universal joints

Replace components, as required. Refer to Propeller Shaft Replacement .

Worn or loose propeller shaft center support bearing

Replace components, as required. Refer to Propeller Shaft Replacement .

Worn axle shaft constant velocity joints

Replace the constant velocity joints, as required.

Loose rear differential mounts or worn bushings

Tighten the mount bolts or replace, as required.

Incorrect oil in the transfer case

Replace the oil with GM P/N 12378261 (Canadian P/N 10953455).

Bearing noise within the transfer case

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

  1. Inspect for the proper fluid level and fill, as required.
  2. If the noise continues, replace the transfer case, as required.

Gear set whine noise within the transfer case

Whine type noises will increase or decrease relative to the vehicle speed.

  1. Inspect for the proper fluid level and fill, as required.
  2. If the noise continues, replace the transfer case, as required.
  3. Contributing factors may include:

    • Incorrect backlash between the gear set
    • Worn or damaged gear teeth
    • Transaxle assembly noise
    • Differential noise