DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case.

Review the Symptoms - Transfer Case and perform the necessary inspections.

Incorrect fluid level or incorrect fluid

1. Inspect the transfer case for the correct fluid level. Refer to Transfer Case Fluid Replacement .
2. Inspect the transfer case for the correct type of fluid.
3. Flush the transfer case, and fill with the correct fluid, if required. Refer to Approximate Fluid Capacities .

Worn or faulty planetary differential

1. Inspect the planetary differential for the following conditions:

•	Loose planetary differential splines to the input shaft splines

•	Loose or faulty pinion gears

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4476/79 Unit Repair.

2. Replace the planetary differential assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4476/79 Unit Repair.

Worn or missing sun gear thrust washer

1. Inspect to ensure the thrust washer is installed.
2. Inspect the thrust washer and mating surface for excessive wear.
3. Replace the worn or missing thrust washer. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4476/79 Unit Repair.

Worn or damaged rear sun gear

1. Inspect the sun gear external gear teeth for excessive wear.
2. Inspect the sun gear-to-rear output shaft for excessive looseness.
3. Replace the sun gear or rear output shaft if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4476/79 Unit Repair.

Rear output shaft bearing outer retaining ring

1. Inspect for the following conditions:

•	Proper installation of the rear output shaft bearing retaining ring

•	Excessive wear or damaged retaining ring groove in the rear case half

2. Repair or replace the following components if found faulty:

•	Properly install a new rear output shaft 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 in Transfer Case - BW 4476/79 Unit Repair.

Worn or loose chain

1. Inspect for a loose chain, excessive wear on the snubber or deep gouges in the lining.
2. Replace the chain, sprockets and snubber. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4476/79 Unit Repair.