Got a friend with a 80 swao in a 88-98 and it pushes out the tail seal when he runs it on the interstate. It is a 96 model with the trans fittings close together and has a trans go in it. Any ideas?

 

If my memory is correct, these is a restrictor piece that gets pressed into the rear of the main case that restricts oil to the rear bushing. You can access it by removing the tail cone. perhaps it popped out or something causing excess pressure at the rear bushing and forcing out the seal? Is it also blowing out oil?

 

I had this issue once and the yoke was the problem, had a small vibration in it and wore the bearing that's in the extension housing and knocked the seal out, sending oil everywhere. check with him and see if he has any drivetrain vibrations

 

Same issue i am having with mine have replaced my ext housing already once

 

Well, what did you find or still working on it?