Gearbox seals?

[tdskip]

Good morning, happy weekend to everyone.

My engine is out of the S4 and before I put it back in it seems like a good idea to consider the seals on my gearbox. This car has been sitting for close to 20 years, so I would imagine that they might be a bit leaky and better to address them now than later. Yes/no/maybe?

Does the gearbox have to come out to do this or can I do that in place? Any tips or coaching to pass along?

Thank you again for all of the help and encouragement, it is very much appreciated and hopefully it is obvious that I?m trying to take good care of this car.

[SENC]

It is a good bet that the tailshaft extension housing seal needs to be renewed, and while others have done so in situ mine required a good bit of convincing and I couldn't have done it without the gearbox out. I removed engine and gearbox in 1 piece, but removing the gearbox with engine already out should be fairly simple.

I had lots of road gunk and buildup in my gearbox mount and couldn't get to the bolt heads to detach mount from box, so just detached from the frame instead and removed the mount from the gearbox once out. Once the mount is detached from either frame or box, the gearbox will slide forward out of the well and leave the propshaft behind. Drain the gearbox first or you'll dump the oil out of the tailshaft extension when removed.

You can remove the tailshaft extension from the main box without getting into the transmission innards in any signficant way - you'll just need a new gasket for reinstall. The extension can then be set on its wide end and you can pry the old seal out. When I did this and inspected the bushing just below, I noted a lot of scoring - which prompted me to pull the propshaft and inspect the yoke. Clearly something had gotten in there and I found it so worn that even a new seal in the extension wouldn't have kept oil in. I have a recent thread on pulling and rebuilding my gearbox that you can check for pictures.

[tdskip]

Thank you for the very thoughtful and super helpful response. I will pull the gearbox out and go through it.

Doing things right can be such a pain. Grin.

[2cams70]

Depends on their condition. Time in itself does not hurt synthetic rubber seals. Heat and usage does. If you are going to touch the gearbox best to budget on a complete checkover, bearings, synchro rings etc. and not just seals.