Tiptronic - procedure to replace driver's side output shaft seal
 

My tip transmission is out of the car for an IMS/RMS replacement, and while I'm at it, I thought I would also replace the driver's side output shaft seal (also known as the long side, or the left side seal) It looks like it has a tiny leak.

I replaced the passenger side output shaft seal last year and it was relatively easy, but I can't find any instructions or procedure to replace the driver's side on the internet or in my service manual. I searched a lot here, and just found other folks who also couldn't find information on this particular procedure.

Has anyone done this before, and can you write up a short overview, or does anyone have access to a service manual that has directions for this procedure that you can share?

I've got a 2001 Boxster S Tiptronic...



Thanks,



Dan

Well I opened up the differential and answered my own question. It looks like I had a bunch of gunk covering the output shaft, but no leak. And my learning for this part is - if the drivers side is not leaking, don't fix it!

To get the driver's side output shaft out remove the three bolts securing the triangular cover behind the drivers side shaft. Once you remove the bolts, the cover and shaft slide out of the diff as an assembly.

Now - note there are two seals. There is a simple seal like a squared off o-ring about 3 inches in diameter that seals off the triangular cover. If you had a leak from the edge of the cover, this would be the seal to replace. In my case the seal stuck to the differential housing. If this happens to you, remove it, clean it, and then reinstall it in the groove on the back of the triangular cover.

There is also a shaft seal - this is what I had assumed I should be replacing since it's counterpart of the passenger side had been leaking badly. This would be the seal to replace if you saw a leak coming from around the output shaft. Unfortunately, the drivers side shaft seal is hidden behind a what appears to be press-fit bearing. I removed the snap ring retaining the bearing, and the bearing was still stuck on tight. So I am going to leave the whole thing alone.

The net is that it looks to me like if you do get a leak coming from the drivers side output shaft, you will need a new bearing as well as a new seal, and you'll need to press off the old bearing, replace the seal and then press on a new bearing. If you get a leak coming from the edges of the cover on the drivers side, you are in luck and you just have a simple o-ring like seal to replace.

I thoroughly cleaned and re-oiled the bearing before reassembly


The passenger side is much easier. Remove the single bolt in the center of the output shaft. Pull the output shaft out. The seal is right in front of you, and it's easy to remove and replace.


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Thanks for posting. Just out of curiosity, did you have to remove the passenger side shaft to get the driver's side out, or did you just do it to get to the passenger side seal? If the former, what does removing the passenger side shaft do to facilitate removal of the driver's side?

I just checked and you are correct.

I had assumed that the long bolt that passes through the center of the passenger side differential cover and shaft then screws into the end of the drivers side shaft.

This is not the case; you don't need to remove the passenger side to remove the driver's side.

Thanks for clarifying. Luckily mine's leaking on the passenger side. If it ever leaks on the driver's side, thanks to you I'll know that I'll need time to take it out and to a machine shop to press out the bearing. :cheers:

You are very welcome.

One thing you might consider is that when you change the seal on the passenger side, also crack open the housing on that side so you can get all of the old differential oil out. Mine had clearly never been changed before and it was disgusting.

I would recommend buying a new housing o-ring in addition to the new differential seal if you decide to do this.

in my case I changed the fluid once, drove a little bit and changed the fluid again, but if I did it again I would probably drain the differential completely.

Thank you. I decided to do it sooner rather than later. I just ordered the parts from Pelican, including the housing seal. It's on special order and it took me a while to find it, but I did!