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 Transfer Case Fluid Replacement .

Excessive clearance between the slip yoke and the rear output shaft

1. Inspect for the following conditions:

•	Worn slip yoke splines

•	Worn rear output shaft splines

2. Repair or replace the following components if faulty:

•	Replace the slip yoke, if required. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.

•	Replace the rear output shaft, if required. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 149-NP3 Unit Repair.

Excessive clearance between the slip yoke and the rear bushing

1. Inspect for the following conditions:

•	Worn rear bushing

•	Worn slip yoke bushing journal

2. Repair or replace the following components if faulty:

•	Replace the slip yoke, if required. Refer to One-Piece Propeller Shaft Replacement or Two-Piece Propeller Shaft Replacement in Propeller Shaft.

•	Replace the rear bushing if worn. Refer to Rear Output Shaft Seal Replacement .

Worn or faulty planetary carrier

1. Inspect the planetary carrier for the following conditions:

•	Worn annulus gear

•	Worn or faulty planetary gears

•	Loose planetary gears

•	Planetary carrier to mainshaft splines for wear

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - NVG 149-NP3 Unit Repair.

2. Replace the planetary carrier assembly and annulus gear if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 149-NP3 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 - NVG 149-NP3 Unit Repair.

Worn or damaged sun gear

1. Inspect the sun gear external gear teeth for excessive wear.
2. Replace the sun gear or rear output shaft if worn. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - NVG 149-NP3 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 149-NP3 Unit Repair.