GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: The transfer case is not delivering engine torque to the front propeller shaft.

Clutch pack failed or burnt

  1. Inspect the clutch pack for the clutch plates being burnt or worn.
  2. Disassemble the transfer case and the clutch assembly. Refer to Transfer Case Disassemble in Transfer Case - NVG 136-NP4 (One Speed Automatic) Unit Repair.
  3. Inspect the following components for being faulty. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 136-NP4 (One Speed Automatic) Unit Repair.
  4. • Clutch discs for being burnt
    • Clutch discs for worn friction material
    • Clutch lever for excessive wear
    • Apply plate for a failed bearing
  5. Assemble the transfer case and clutch assembly. Shim the clutch assembly to the correct specifications. Refer to Transfer Case Assemble in Transfer Case - NVG 136-NP4 (One Speed Automatic) Unit Repair.
  6. Inspect the front differential for the correct fluid. Refer to Lubricant Change in Front Differential.
  7. If the vehicle is used in cold climates, replace the front differential fluid with a synthetic fluid. Refer to Lubricant Change in Front Differential.

Broken apply plate

  1. Disassemble the transfer case and inspect for the apply plate being broken. Refer to Transfer Case Disassemble and Transfer Case Cleaning and Inspection in Transfer Case - NVG 136-NP4 (One Speed Automatic) Unit Repair.
  2. Replace the apply plate and other components that have been damaged. Refer to Transfer Case Assemble in Transfer Case - NVG 136-NP4 (One Speed Automatic) Unit Repair.