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 shaft thrust bearings

1. Inspect for worn or missing input shaft thrust bearings. Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.
2. Replace the thrust bearings, as required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

2/4 Wheel drive synchronizer assembly

1. Inspect the synchronizer for the following conditions:

•	The synchronizer hub for not being press fit on the rear output shaft splines

•	The synchronizer sleeve to the synchronizer hub for wear

•	The synchronizer sleeve to the drive sprocket engagement teeth

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the synchronizer assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 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 - Isuzu T150 Unit Repair.

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Range sleeve

1. Inspect the range sleeve for the following conditions:

•	Worn engagement teeth

•	Worn internal splines

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - Isuzu T150 Unit Repair.

2. Replace the range sleeve if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.

Front output shaft yoke

1. Inspect the front output shaft yoke for the following conditions:

•	Yoke flange nut loose

•	Yoke loose fit on the front output shaft

2. Replace the yoke flange nut if loose. Refer to Front Output Shaft Seal Replacement .
3. Replace the yoke if the internal splines are worn. Refer to Front Output Shaft Seal Replacement .
4. Replace the front output shaft if the splines are worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - Isuzu T150 Unit Repair.