Transfer Case Clunk During Acceleration and Deceleration

WARNING: This page is about a different car, the 2023 GMC Sierra 3500 HD and 2023 GMC Sierra 2500 HD. 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 when it is in AWD 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. Inspect the transfer case for the correct type of fluid. Approximate Fluid Capacities Flush the transfer case and fill with the correct fluid, if required. Transfer Case Fluid Replacement
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, if required. Propeller Shaft Front Slip Yoke Replacement (1 Piece, L5P) , or Propeller Shaft Front Slip Yoke Replacement (1 Piece, L8T) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L8T without Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L8T with Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L5P without Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L5P with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L5P with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L5P without Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L8T with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L8T without Chassis Cab - 310/314) Replace the rear output shaft, if required. Transfer Case Disassemble (with MYD) , or Transfer Case Disassemble (with MGM, MGU) , and Transfer Case Assemble (with MYD) , or Transfer Case Assemble (with MGM, MGU)
Excessive clearance between the slip yoke	Inspect for the following conditions: Worn rear bushing Worn slip yoke bushing journal Repair or replace the following components if faulty: Replace the slip yoke, if required. Propeller Shaft Front Slip Yoke Replacement (1 Piece, L5P) , or Propeller Shaft Front Slip Yoke Replacement (1 Piece, L8T) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L8T without Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L8T with Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L5P without Chassis Cab - 310/314) , or Propeller Shaft Front Slip Yoke Replacement (2 Piece, L5P with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L5P with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L5P without Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L8T with Chassis Cab - 310/314) , or Propeller Shaft Rear Slip Yoke Replacement (L8T without Chassis Cab - 310/314)