GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 2HI mode.

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

Incorrect fluid level or incorrect fluid

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

Excessive clearance between the slip yoke and the rear output shaft

  1. Inspect for the following conditions:
  2. • Worn slip yoke splines
    • Worn rear output shaft splines
  3. Repair or replace the following components if faulty:
  4. • Replace the slip yoke, if required. Refer to Rear Propeller Shaft Replacement in Propeller Shaft.
    • Replace the rear output shaft, if required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Excessive clearance between the slip yoke and the rear bushing

  1. Inspect for the following conditions:
  2. • Worn rear bushing
    • Worn slip yoke bushing journal
  3. Repair or replace the following components if faulty:
  4. • Replace the slip yoke, if required. Refer to Rear Propeller Shaft Replacement in Propeller Shaft.
    • Replace the rear bushing if it is worn. Refer to Rear Output Shaft Seal Replacement .

Worn high speed teeth on the range sleeve

  1. Inspect for the following conditions:
  2. • Worn high speed teeth on the range sleeve
    • Worn or missing input gear thrust washers
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 246-NP8 Unit Repair.
  3. Repair or replace the following components if faulty:
  4. • Replace the range collar if it is worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.
    • Replace the thrust washers as required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.

Rear output shaft bearing outer retaining ring

  1. Inspect for the following conditions:
  2. • Proper installation of the rear output shaft bearing retaining ring
    • Excessive wear or damage to the retaining ring groove in the rear case half
  3. Repair or replace the following components if found faulty:
  4. • Properly install a new rear output shaft bearing outer retaining ring.
    • Replace the rear case half if the retaining ring groove is excessively worn.
    • Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 246-NP8 Unit Repair.