ZF transmisson input shaft seal leaking

[surebimmer]

Lubed seal before pressing on. I can look and see if i can find specs.

[e30serg]

Wrong tranny fluid perhaps? Seal backwards (Is that even possible?)?
When you take the tranny out, can you spin the output shaft and see where it's leaking from?
Maybe it only does it when it's really hot? Over-expanding fluid?
Is there a pressure-relief valve that's plugged?

[e30serg]

Any updates on this?

[surebimmer]

Nope i'm car poor right now. Looking at a 6 speed or 5 speed from my friend Craig.

[sushipower]

This may sound crazy. Being that the ZF trans use ATF oil, it must have some type of internal pump that helps lubricate the gears and shaft. By chance is there a bolt on the front of the input shaft or somewhere near? Itt could be leaking from there and all that is needed is some teflon tape.

[Rev Engineer]

surebimmer - any update!?

I've got the same problem here and I can't figure it out. With the first s50 transmission I used, I couldn't stop a leak at the back of the transmission. The leak turned out to be coming from the vent at the top of the transmission. I couldn't fix it so I replaced it with a transmission from a junk yard. This one leaked out the front seal and oil soaked the clutch disc. I replaced the seal and put the transmission back in. It held up for a few days, but it started leaking again. I now have the transmission out and I'm not sure what to do next.

I'm guessing that the original seal went bad because I pressure washed the tranny and I might have gotten water inside the release bearing tube. There was some corrosion on the input shaft when I had it all apart the first time. I pushed the new seal in further than the original to get it further away from the slight corrosion, but I noticed that the drag on spinning the input shaft increased when I tapped the seal in further. I was a little concerned at the time, but I didn't have another seal to work with so I just put the tranny back in. A day at the track and the leak was back again in full force. I hope that I just screwed up replacing the seal and doing it again will fix it this time, but surebimmer's story really scares me.

I'm open to using my other transmission if anyone has an idea of how to fix the vent leak!? That one didn't leak out of the front seal. BTW - The play in the input shaft between the transmissions is very similar.

[surebimmer]

I picked up a used transmission and repalced the leaking one. No issues with the new used one. Thinking about getting the leaking one rebuilt but we used trans on craigs for $300-400 bucks its hard to justify the cost.

[Rev Engineer]

Thanks for the updated, but wow!! That's not what I wanted to hear... I replaced the original one because I couldn't fix the vent leak, now I might have to replace this one because the input leaks. FML Anyone want to buy 2 leaky ZF transmissions!? I should have gone the getrag route...