Hey there, I have a 98 1500 ram 4x4 with 360, NP 231 transfer case, and auto trans. I started to feel a light grinding while in 2wd. then with the recent snow I tried using my 4wd. It works, but it grinds and growls terrible. It is the worst when turning. In fact I put it up on jack stands and ran it in 4wd and when we turned the wheels it soudned like something was going to fall off. The U joints all seems to be tight and in good shape as do the wheel bearings. It seemed as though it was coming from the T case, and it was confirmed by a local small mechanic shop. I changed the case with a used one, and it is doing the same thing. I don't have the time for the truck to be out of commission right now so I decided to take it to the dealership. They said the 4wd vaccuum switch is bad and not properly engaging 4wd. They are going tofix it tomorrow. This doesnt seem like that would cause this issue. Any one have any thoughts?

 

It could keep the fork from engaging the front axle completely which would cause some unusual noises.

 

rear output shaft snap ring......