PDK Shift Mechanism Won't Change Gears

[JCyoda 1]

Went to the garage, started my car, pulled out of the garage, braked to stop to check that my garage door closed (5 sec max), applied some gas and nothing happened. When I tried to change the gear selection, the gear indicator in the tachometer didn't show at all.  Pushed it back into the driveway as best I could. I have tried it several times with no luck. No fault lights have come on!!  I looked here in the forum but didn't see any postings that were similar.  Five days previous to this event, I returned from a spirited, three state sampling (1900mi) of the twistys and mountain roads, only smiles as a result.  Anyone have any thoughts?

 

Edited August 25, 2019 by Loren
Removed "SHOUTING" from title

[dammad 6]

Do you have a durametric you can use to pull some codes? I believe the PDK will flash something in the gear indicator if it is in limp home mode but this may be more subtle than that.


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[JCyoda 1]

Yes, I have a "FIXD" device that reads the codes, and told me that there were no error codes!!🙁 Maybe I will go check again.  Thanks for the note.

[JFP in PA 668]

7 hours ago, JCyoda said:

Yes, I have a "FIXD" device that reads the codes, and told me that there were no error codes!!🙁 Maybe I will go check again.  Thanks for the note.

 

Many OBD II scanners do not successfully read Porsche codes, particularly for something like the PDK.  You need a Porsche specific tool (Durametric, PIWIS).

[JCyoda 1]

Just to be clear, the shifter isn't frozen, it seems normal, but seems like the transmission doesn't get the message.

[JCyoda 1]

I now have it in for diagnosis at a reputable Porsche shop.

[ltcjmramos 0]

Please, do report back on findings.

[JCyoda 1]

Well, I have the diagonsis now and the result is grim!  After multiple attempts to reset the PDK brain, the conclusion is that i need another (new) transmission to the tune of about $25K for R&R and new transmission.    This a know problem tho' rare. Remindes one of something called "IMS"! Eh?

I am getting a second opinion, but I think I am screwed.  If I sell it as is, it's a big lose and I still need a "new" car, or if I fix it the bottom line on my investment goes up by 25K but I still have my Porsche..... I guess it is a no-brainer.  😒

[JFP in PA 668]

40 minutes ago, JCyoda said:

Well, I have the diagonsis now and the result is grim!  After multiple attempts to reset the PDK brain, the conclusion is that i need another (new) transmission to the tune of about $25K for R&R and new transmission.    This a know problem tho' rare. Remindes one of something called " IMS"! Eh?

I am getting a second opinion, but I think I am screwed.  If I sell it as is, it's a big lose and I still need a "new" car, or if I fix it the bottom line on my investment goes up by 25K but I still have my Porsche..... I guess it is a no-brainer.  😒

 

Sorry to hear of your predicament.  The PDK is ultra complex internally, with even the dealer techs limited to what they can do to repair them.  These internals require very specialized fixtures and tooling, which is beyond even the dealer’s capabilities.  Good luck with your next steps.......

[JCyoda 1]

Thanks for that, I guess it is the price we pay to develop mind-blowing technology.

[vanHunks 0]

I was surprised to read that the solution to a control problem is replacing the entire gearbox - this seems (in the absence of any other information) to be excessive. Rennlist has a good sticky on repairing PDKs.  In any case Porsche needs to introduce some exchange program so that the value in the "broken" gearbox is returned to the customer. In this case, for instance, I speculate that the mechanical components, clutches etc are entirely serviceable. The current arrangement makes the customers with the first-generation PDK boxes the gamma-testers of a new device. It would be interesting to PDK compare failure rates in the 997 with the later 991s and 992s.

[JFP in PA 668]

Welcome to RennTech 

As noted above, Porsche, like may other OEM's, has restricted what repairs are permitted in the field with their SMG (read PDK) transmissions.  Dealer techs are limited to a very short list of things to check, including software updates, before they resort to replacing the gearbox.  And, like other brands, there is no plans for an exchange program where the vehicle owner gets anything more than a core value for the used gearbox because it would be impractical for Porsche or any other OEM to tear down and access the level damage to the components in a timely manner, so a value retention program is little more than wishful thinking.  Porsche, again like other brands, has also dramatically restricted the availability of parts for these transmissions, partially because aftermarket vendors were purchasing them and then significantly modifying them before selling them to the public.  The wet clutch assembly is a good example; Porsche had made it available as an over the counter part number for around $5K (US), but stopped doing so when cars came in with the modified clutches failing and damaging other component's in the gearboxes. Net result is that you can now only find sump pans, filters, and fluids for these gearboxes; anything beyond that gets very expensive very quickly.

[Silver_TT 14]

This is even the case with pre-PDK gearboxes like the Getrag manual gearbox for my 996TT that was damaged due to the previous owner using non-OE fluid (HUGE no-no).  Take that TT to a Porsche dealer and the only answer you're going to get is buy a new gearbox.  Fortunately for the pre-PDK gearboxes they can be repaired -- but there is only one shop in the entire USA that is a lock for this extremely specialized job and it ain't cheap.  But a new PDK gearbox is like $15-20K last I checked so......... (edit: the poster above says $25K, even worse)

Edited October 23, 2020 by Silver_TT