DEFINITION: A faulty internal transfer case component that causes a growl or grinding noise in the transfer case while the vehicle is turning.

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

Planetary differential

1. Inspect the planetary differential pinion gears for the following conditions:

•	Chipped, bent or deformed teeth

•	Pinion gear bushings worn

•	Pinion gear thrust washers missing

•	Seized or binding pinion gears

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4479 - Unit Repair.

2. Inspect the planetary differential for deformation. Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4479 - Unit Repair.
3. Replace the planetary differential assembly if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4479 - Unit Repair.

Sun gears

1. Inspect the sun gears for the following conditions:

•	Gear tooth failure

•	Worn or galled thrust surfaces

•	Refer to Transfer Case Cleaning and Inspection in Transfer Case - BW 4479 - Unit Repair.

2. Replace the sun gears if faulty. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4479 - Unit Repair.

Thrust washer

1. Inspect the thrust washer for seizure to the planetary differential.
2. Inspect the thrust washer for galling.
3. Replace the thrust washer if faulty and the mating component if damaged. Refer to Transfer Case Disassemble and Transfer Case Assemble in Transfer Case - BW 4479 - Unit Repair.

Planetary differential not timed properly

1. Inspect the planetary differential for being timed properly. Refer to Transfer Case Assemble in Transfer Case - BW 4479 - Unit Repair.
2. Properly time the planetary differential gears. Refer to Transfer Case Assemble in Transfer Case - BW 4479 - Unit Repair.