Transfer Case Clunk in 2HI Only

WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. 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 while in the 2HI mode. 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 (TrailBlazer, Envoy, Rainier, Bravada) or Transfer Case Fluid Replacement (TrailBlazer EXT, Envoy XL, Envoy XUV) Fill the transfer case to the correct fluid level, if required. 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 the slip yoke splines for wear. Inspect the rear output shaft splines for wear. Replace the slip yoke, if required. Refer to Propeller Shaft Replacement - Rear in Propeller Shaft. Replace the rear output shaft, if required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 226-NP8 Unit Repair.
Excessive clearance between the slip yoke and the rear bushing	Inspect the rear bushing for visible signs of wear. Inspect the slip yoke bearing journal for wear. Replace the slip yoke, if required. Refer to Propeller Shaft Replacement - Rear in Propeller Shaft. Replace the rear bushing if the bushing is worn. Refer to Transfer Case Output Shaft Seal Replacement - Rear .
Worn high speed teeth on the range collar	Inspect for worn high speed teeth on the range collar. Refer to Cleaning and Inspection in Transfer Case - NVG 226-NP8 Unit Repair. Inspect for worn or missing input gear thrust washers. Refer to Cleaning and Inspection in Transfer Case - NVG 226-NP8 Unit Repair.