What to know about the Transfer Case Output Shaft Seal?
Vehicles furnished with four wheel drive employ a gear case to alter among two wheel drive, high gear four wheel drives, neutral mode, and low gear four wheel drives. This gear case is called a transfer case. It uses a chain drive and gear reductions inside so that it can transfer power from the transmission to the rear differential and the front differential according to the driver’s input. The chain and gears spin in fluid that greases and cools the mechanisms inside the transfer case, and seals keep the fluid from leaking out past the input shaft from the transmission and the front and rear output shaft to the differentials. When one or more of these seals leak, fluid not only gets on the undercarriage and ground, but the transfer case is no longer able to effectively cool and lubricate the internal parts. If the internal parts overheat and seize up, or a disastrous failure occurs to the transfer case, the four wheel drive system will not function.
Facts to Note:
The transfer case doesn’t have a fluid level indicator or dipstick. Any fluid leaks should be checked without wastage to avoid internal damage from low fluid.
Seals such as the transfer case output shaft seal will normally sweat due to the output shaft rotation.
How to Fix:
The vehicle is lifted and supported on jack stands
The driveline is detached and transfer case output yoke is removed
The faulty transfer case output seal is taken out and changed with a new seal
The transfer case yoke and driveshaft is reinstalled and the vehicle is taken off the jack stands
The repair is confirmed and the vehicle is road tested for proper operation
The transfer case is not made for any routine maintenance, however, if the transfer case fluid is leaking from either the front or rear seal, one of your expert mechanics needs to remove and change the seal to prevent damage inside the transfer case.
SEE ALSO:WHAT IS PINION SEAL REPLACEMENT
Common symptoms indicating you may need to change the Transfer Case Output Shaft Seal:
Brownish color fluid spots on the ground under the middle of your vehicle
Whining noise when shifting transfer case modes
Grinding noise from under the middle of your vehicle while driving
Rattling noise when driving at highway speeds
Transfer case will not shift between two wheel drive and four wheel drive modes
Importance of this service:
If your vehicle is designed with four wheel drive, the transfer case is integral to its operation. A fluid leak from the transfer case should be addressed in short order to avoid further damage internally, and to prevent your vehicle from being unusable.