DEFINITION: During acceleration or deceleration, a clunk is heard or felt in the transfer case while in the 4HI range only.

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 Transfer Case Fluid Replacement .

Input gear thrust washers

1. Inspect for worn or missing input gear thrust washers. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 263-NP1 Unit Repair.
2. Replace the thrust washers, as required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 Unit Repair.

2/4 Wheel drive synchronizer assembly

1. Inspect the synchronizer for the following conditions:

•	The synchronizer hub internal teeth to rear output shaft splines for excessive looseness caused by wear

•	The synchronizer sleeve engagement teeth to the synchronizer gear for wear

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 263-NP1 Unit Repair.

2. Replace the synchronizer assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 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 - NVG 263-NP1 Unit Repair.

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Worn high speed teeth on the range sleeve

1. Inspect for worn high speed teeth on the range sleeve. Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 263-NP1 Unit Repair.
2. Replace the range sleeve if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 263-NP1 Unit Repair.