Transfer Case Clunk in 4LO (1)

Transfer Case Clunk in 4LO Transfer Case Clunk in 4LO

	Cause	Correction
	DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 4LO range only. It is typical for the vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from transfer case N (Neutral) with the engine running. 1. Review the correct owners manual shifting procedures with the customer. 2. Compare the noise to a similar vehicle and see if a normal condition. 3. Identify the source of the noise using chassis ears and refer to the appropriate service manual section. 4. Note specifics such as when the noise is present (2HI, 4HI, OR 4LO). 5. Note if the noise relative to vehicle speed, is noisy on turns, during acceleration, stops, or other specifics. 6. If the source of the noise is the transfer case, inspect for the correct fluid level. 7. 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. 1. Check the tire pressure and adjust as required to the value recommended by the label on the vehicle. 2. Road test the vehicle
	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

Cause	Correction
Suspension components worn	Replace the suspension components as required. Noise Diagnosis - Front Suspension or Noise Diagnosis - Rear Suspension
Tire scuffing 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 a tire scuffing type noise and is to be considered a normal condition and operating characteristic of a part-time 4WD system. Operated the vehicle in 4WD performing low speed left and right turns to confirm a tire scuffing type noise.
Transfer case planetary carrier gears worn	Note: A clunk in 4HI noise that increases in 2HI only may be caused by inspect for worn or damaged planetary gears and ring gear damage. A clunk in noise that occurs in either 2HI or 4HI may be caused by worn planetary gear needle bearings or shafts. A clunk that occurs in 4LO may be caused by worn planetary gears or annulus gear. Repair as required 1. Inspect for the following: Chipped, bent, or deformed teeth Planetary gear needle bearings worn Planetary gear thrust washers cracked or missing Seized or binding planetary gears 2. Replace the planetary components as required.