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 4LO range only.

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

High/low planetary carrier assembly

  1. Inspect for the following conditions:
  2. • Excessively worn planetary gears
    • The planetary gears loose in the planetary carrier
    • Excessively worn range sleeve engagement teeth on the carrier
    • Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 233-NP1 Unit Repair.
  3. Replace the high/low planetary if any of the above conditions are found. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 233-NP1 Unit Repair.

Annulus gear

  1. Inspect the annulus gear to front case fit for any looseness.
  2. Replace the front case half if the annulus gear is loose. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 233-NP1 Unit Repair.

Range sleeve

  1. Inspect the range sleeve engagement teeth for excessive wear.
  2. Inspect the range sleeve to mainshaft splines for excessive wear.
  3. Replace the range sleeve if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 233-NP1 Unit Repair.