Transfer Case Clunk In 4HI

WARNING: This page is about a different car, the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, and 2018 Chevrolet Suburban. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Action
DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 4HI range only. Compare the noise to a similar vehicle and see if a normal condition. Identify the source of the noise using chassis ears and refer to the appropriate service information. Note specifics such as when the noise is present (2HI or 4HI). Note if the noise relative to vehicle speed, is noisy on turns, during acceleration, stops, or other specifics. If 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.
Tire pressure uneven	NOTE: A clunk condition that occurs when performing slow speed turns in 4WD may be caused by low or uneven tire pressure. Set the tires to the recommended vehicle tire pressure for evaluation to see if the noise goes away. Upon completion of the test, reset the tire pressure to the correct pressure as recommended on the tire.
Transmission or transfer case mounts loose or damaged	Repair or replace the mounts as required
Propeller shaft center support bearing worn (as applicable)	Replace the center support bearing as required. Refer to Symptoms - Propeller Shaft .
Propeller shaft universal joints worn	Replace the universal joints as required. Refer to Symptoms - Propeller Shaft .
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.
Suspension components worn	Replace the suspension components as required. Refer to Noise Diagnosis - Front Suspension or Noise Diagnosis - Rear Suspension .
4WD gear noise	NOTE: A growl or clunk that occurs with vehicle in 4WD at low speed in a tight turning radius situation may be caused by the gears and chain and is to be considered a normal condition and an operating characteristic of a 4WD system. Operate the vehicle in 4WD performing low speed left or right turns to confirm a transfer case gear noise.
Transfer case rear output shaft rear bearing retaining ring- incorrectly installed	Inspect for the following: Improperly installed rear output shaft rear bearing outer 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 and Transfer Case Assemble .