Hello group,

I have a customer who has gear oil in their automatic fluid. I did some
research (both on the archives here and several other sites) and found which
seals are commonly to blame. I called one of the major Vanagon parts
retailers and told them the problem with the automatic and that I needed the
seals to fix it. I didn't receive the mainshaft seals that go back to back
and those are the ones that seem to be to blame. So, I called the major
transmission rebuilder in Oregon who does automatics and a major one here in
california and they both told me that the transmission needs a rebuild
because the differential bearings wear cause the mainshaft to have some play
and then the seals go bad. They both said that was the only cause of the
seal failure.

Who am I to argue with people who rebuild them for a living? It's just tha
in the past on several forums nothing about the bearing was mentioned, just
the seals.

On this trasmission the bearings on the differential on the sides where the
output flanges are seem quite tight. Seemingly not enough to make a shaft
that doesnt even ride on them wobble enough to make a leak.

Now that the fluids have exchanged a rebuild may be due because the clutches
might be soaked in gear oil and the differential might be damaged if it has
been running in thin automatic fluid. Assuming this problem was caught
quickly and those parts are ok is a rebuild really necessary or is it really
ALWAYS a sign of worn differential bearings?

thanks!