cgfen

My recently purchased 93 with tiptronic has a sick transmission.
It seems to shift reasonably well when cold and all 4 gears can be utilized.
When warm, the trans seems to hang in second and won't shift to third.
Commanding via manual mode does not enable shift to third.
Unsure about 2 to 4 shift since I've only tested at low speeds since discovering the issue.

I plan to put it on my lift this weekend and do a visual inspection, check fluid level, etc.

1) Do you know if this transmission is used in any other Porsches?
2) Can you point me to transmission fluid R&R service guide? I'm unsure if its as simple as drain, change filter and refill.
3) If you have experience servicing these tranny's would love to start a dialog.

Thanks

Craig

Zirconocene

I hope someone answers, because the Cayman I've been trying to resuscitate is also having some Tiptronic issues.

I recently completed a filter change and (somewhat) flush, and it helped significantly; I think that the transmission was significantly low on fluid. I don't totally understand automatics, but what I've been able to piece together indicates that low fluid can cause for pressures in the valve body that don't work for some of the required shift patterns. Or something like that; valve bodies are black magic to me.

At a very minimum, I don't think that a small round of filter change and fluid flush would hurt anything and it's pretty straightforward on the contemporaneous 928 automatics.

Good luck

RABjr

Maybe start here and ask these experts to get you in the right direction.

https://www.topendmotorsports.com/po...vice-10977.php

https://www.gmpperformance.com/produ...que-converter/

Paul Waterloo

I am no guru, but you can download the workshop manual here, some parts are missing: http://audipages.com/968/manual/

I quickly found this video on a 928:
Best of luck.

Paul Waterloo

Looking at the WSM, page 294 has troubleshooting for no shift 2-3 and 3-2, lots and lots of good info in that section and on page 313 is shows how to check the ATF level and then change it. If you don't find anything obvious the first thing I would do is change the fluid and filter.

cgfen

Paul, thanks for the replies.
"If you don't find anything obvious the first thing I would do is change the fluid and filter.".
I mostly agree, but have seen where this did not good or actually reduced functionality on some old muscle car automatics.

Be well.

Craig

KevinGross

Hi Craig, the factory 968 workshop manual includes both diagnosis guidance as well as information on replacing what they call the "hydraulic control unit." Your problems may indeed lie in that control unit, from your description.

I service Porsche manual transmissions, but will confess to no experience with automatics and Tiptronics.

Kevin
Catellus Engineering, Inc.

cgfen

Thanks Kevin.
I wonder if the "hydraulic control unit." is the valve body?????
I found a used, low mile trans at a breaker, that has been on their shelf since 2002!!
Should have it in 2 - 2 days

I'm going to try swapping valve bodies as first step.
Be well.

cgfen

Paul, thanks for the linky of the video.

KevinGross

I believe that is the case.