GM Service Manual Online
For 1990-2009 cars only

Cause

Action

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in 4HI range only.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Incorrect fluid level or incorrect fluid

    • Inspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement .
    • Inspect the transfer case for the correct type of fluid.
    • Flush the transfer case and fill with the correct fluid, if required. Refer to Transfer Case Fluid Replacement .

Worn high speed teeth on the range sleeve

  1. Inspect for worn high speed teeth on the range sleeve. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 236-NP8 Unit Repair.
  2. Replace the range sleeve if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 236-NP8 Unit Repair.

Worn or missing input gear thrust washers

Inspect for worn or missing input gear thrust washers. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 236-NP8 Unit Repair.

Rear output shaft bearing outer retaining ring

  1. Inspect for the following conditions:
  2. • Properly installed rear output shaft bearing retaining ring
    • Excessive wear or damage to retaining ring groove in the rear case half
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 236-NP8 Unit Repair.
  3. Repair or replace the following components if found faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 236-NP8 Unit Repair.
  4. 2.1. Replace the rear output shaft bearing outer retaining ring.
    2.2. Replace the rear case half if the retaining ring groove is faulty.