Transfer Case Clunk in 2HI Only

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: A faulty internal transfer case component that causes a clunk that is heard or felt during acceleration or deceleration with the transfer case in 2HI mode only. Compare the noise to a similar vehicle to see if a normal condition. Identify the source of the noise using chassis ears and refer to the appropriate service information section. Note specifics such as when the noise is present (2HI, 4HI, OR 4LO). Note if the noise relative to vehicle speed, is noisy on turns, or other specifics. F the source of the noise is the transfer case, inspect for the correct fluid level. Inspect the drain plug for large metal deposits. Small metal flakes and fine metal dust on the plug magnet are to be considered normal. Review the Symptoms - Transfer Case and perform the necessary inspections.
Transmission or transfer case mounts loose or damaged	Repair or replace the mounts as required.
Rear propeller shaft center support bearing loose or damaged (as applicable)	Replace the center support bearing as required. Refer to Symptoms - Propeller Shaft .
Rear propeller shaft universal joints worn	Replace the universal joints as required. Refer to Symptoms - Propeller Shaft .
Transfer case rear output shaft bushing worn	NOTE: An excessively worn bushing may be indicated by a leaking rear output shaft seal. Replace the rear output shaft bushing and propeller shaft slip yoke as required.
Suspension components worn	Replace the Suspension components as required.
Front axle actuator shift noise	NOTE: When shifting from 2WD-to-4WD or 4WD-to-2WD, the front axle actuator may be heard engaging or disengaging and the axle internal components shifting. This is to be considered a normal condition. Shift from 2WD-to-4WD and from 4WD-to-2WD to determine if the noise source is the front axle to determine if this is a normal condition.
Rear output shaft spline-to-propeller shaft slip yoke spline- excessive clearance	NOTE: A clunk condition in 2WD heard when the vehicle comes to a stop or from a stop-to-acceleration situation may be caused by excessive clearance between of the splines of the rear output shaft and propeller shaft slip yoke. Replace the following components: Rear output shaft. Refer to 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) . Propeller shaft slip yoke. Refer to.PROPELLER SHAFT REAR SLIP YOKE REPLACEMENT .
TRANSFER CASE REAR OUTPUT SHAFT REAR BEARING RETAINING RING INCORRECTLY INSTALLED	Inspect for the following: Improperly installed rear output shaft rear bearing retaining ring. The snap ring is to be installed completely into the OD groove of the bearing. Excessive wear or damaged retaining ring groove in the rear case half. Repair or replace the following components AS REQUIRED: Properly install a new rear output shaft rear bearing outer retaining ring. Replace the rear case half if the retaining ring groove is excessively worn. Refer to 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) .