DEFINITION: A faulty internal transfer case component that causes a whine or rumble noise in the transfer case.

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

Faulty bearings

1. Inspect all of the bearings and journals. Refer to Transfer Case Front Half Cleaning and Inspection , Transfer Case Rear Half Cleaning and Inspection , Rear Output Shaft Cleaning and Inspection , Front Output Shaft and Input Shaft Cleaning and Inspection and Drive Chain, Drive Sprocket, and Driven Sprocket Cleaning and Inspection in Transfer Case - NVG 120-NR9 Unit Repair.
2. Replace any faulty bearings, and any components with faulty bearing journals. Refer to Front Output Shaft Drive Sprocket Bearing Replacement , Front Output Shaft Rear Bearing and Rear Output Shaft Bearing Replacement , Input Shaft Thrust Bearing Replacement and Front Output Shaft Bearing and Front Input Bearing Replacement in Transfer Case - NVG 120-NR9 Unit Repair.