Got a 70 vette, 454, with 4 speed Muncie M20 that leaks transmission fluid. Have taken it out and apart, but not sure what seals are needed. I want to replace them all while I have it out, as well as the gaskets. Based on the #'s, the muncie was rebuilt by the previous owner from 67 and 68 parts. The good news is the gears all look in excellent shape.
If you know, please advise as to what seals I will need to buy.
There are several places who will put a steel sleeve in your case for that shaft Gary's68 is talking about.That would permanently end that leak. Trying to seal it won't last when the case hole becomes egg shape. That is a very common source of a slight leak.