Transfer case, what goes wro?ng?

[ponkotsu]

I have to pull the transfer case on my Aviator to fix the cover gasket. As long as I have it out, I'm thinking I should tear it down and rebuild it. But as far as I know, there really isn't much that goes wrong with them. Seems like they are pretty much good for the life of the vehicle.

Maybe just change the shaft seals? Any way to check the viscous coupling is okay?

 

[imp]

I have to pull the transfer case on my Aviator to fix the cover gasket. As long as I have it out, I'm thinking I should tear it down and rebuild it. But as far as I know, there really isn't much that goes wrong with them. Seems like they are pretty much good for the life of the vehicle.

Maybe just change the shaft seals? Any way to check the viscous coupling is okay?

You didn't mention mileage, but as far as I know, the viscous couplings are pretty bullet-proof. I replace shaft seals as a matter of course when opening up any such unit. Seals wear out. Check shaft surfaces for "grooving" from seal lip contact. If grooving is present, see if actual seal location can be altered enough to locate new seal lip next to groove, rather than right on it. In the case of output shaft having a U-joint flange, it is often advisable to replace the yoke if deeply grooved.

A usually ignored component also should be checked for wear (play), if your unit has the Constant Velocity Joint at the front driveshaft to transfer case location. imp