GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

DEFINITION: A faulty internal transfer case component that causes a grating noise in the transfer case while in the AWD, 4HI, or 4LO mode.

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

Broken clutch apply plate

  1. Inspect for a broken clutch apply plate. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 236-NP8 Unit Repair.
  2. Replace the apply plate and the transfer case components that are damaged from debris. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 236-NP8 Unit Repair.

Faulty clutch apply plate bearing

  1. Inspect for a faulty clutch apply plate bearing. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 236-NP8 Unit Repair.
  2. Recondition the transfer case components that are damaged from debris. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 236-NP8 Unit Repair.