how do you know is the tranny?i had the same problem no so long ago and it turn out it was the rear drive shaft.a way that you can find out if is the rear drive shaft is by removing it and run your jeep in 4hi,just remember that you have to put something in the back of your
transfer case to cover that hole so you won't get any t-case oil.
i use to think it was the tranny too.[addsig]