Transfer Case Clunk in 2HI Only

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case. 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.
Excessive clearance between the slip yoke and the rear output shaft	Inspect for the following conditions: Worn slip yoke splines Worn rear output shaft splines Repair or replace the following components, if faulty: Replace the slip yoke. Refer to Propeller Shaft Replacement - One Piece and Propeller Shaft Replacement - Two Piece in Propeller Shaft. Replace the rear output shaft. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 Unit Repair.
Excessive clearance between the slip yoke and the rear bushing	Inspect for the following conditions: Worn rear bushing Worn slip yoke bushing journal Replace the slip yoke, if required. Refer to Propeller Shaft Replacement - One Piece or Propeller Shaft Replacement - Two Piece in Propeller Shaft. Replace the rear bushing if worn. Refer to Transfer Case Output Shaft Seal Replacement - Rear .
Input gear thrust washers	Inspect for worn or missing input gear thrust washers. Refer to Cleaning and Inspection in Transfer Case - NVG 263-NP1 Unit Repair. Replace the thrust washers as required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 Unit Repair.
Worn high speed teeth on the range sleeve	Inspect for worn high speed teeth on the range sleeve. Refer to Cleaning and Inspection in Transfer Case - NVG 263-NP1 Unit Repair. Replace the range sleeve if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 Unit Repair.
Rear output shaft bearing outer retaining ring	Inspect for the following conditions: Proper installation of the rear output shaft bearing retaining ring Excessive wear or damaged retaining ring groove in the rear case half Repair or replace the following components if found faulty: 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 263-NP1 Unit Repair.