no i did not do rear main , actually i just rebuilt my motor last weeknd and am putting it in now. And i too had vibration, the cause was the rear seal on transfer case. It was leaking and blown.

 

I don't have any leaks anywhere (well actually I just changed out my rear third to a 4.56 gear set last night, and the brake d block on the rear Axel is leaking now, but other than that nothing leaks). I will take a good look at all the transmission and T case seals when I have them out for the clutch. I will also replace the pilot bearing. Hopefully some of that will help. I know my rear tires are cupped that is a part of the problem too. I am not going to worry too much until that laundry list is finished.