Added connector pinouts and characteristic resistances to the valve body section and the temp sensor section. I will update with sensor pinouts once fully compiled. Thanks to everyone who's sent me additional info.

 

Thank you PV997 for your efforts. I haven't been on RL much lately but recent PDK issues brought me back. I've read the thread with great interest. My issue (this time) appears to be with the supposedly "bullet proof" section of the box. Has any of your research uncovered any information regarding the availability of replacement gears and / or related bearings? I know Porsche doesn't offer anything but was wondering if you've discovered anything through ZF. BGB did my first PDK replacement in fall 2015 for under $10k parts and labor. Out the door. Granted it was before their Cayman/GT4 and racing programs took off but I can't find a Porsche remanufactured PDK for less than $17k, plus shipping, plus labor etc. Thanks in advance.

 

Cloudspin - Sorry you are dealing with this. Unfortunately I really haven't focused on the gearbox section at all as I found very few outright failures when reading all the online failure anecdotes. The gearbox may not be bulletproof but it does appear to fail far less often than the hydraulic section and sensors. You can try but I don't think ZF is going to be much help as another owner contacted them directly and was told they were bound by a confidentiality agreement with Porsche. (Sketchy.)

Can you provide more info about the failure? I ask at the transmission control unit disables shifting functions in response to some sensor failures. So it can seem like there is a problem in the gearbox when it is actually fine, it's simply the TCU forcing the transmission to appear stuck in a gear. This is another really sketchy thing Porsche is doing that makes it seem like a transmission has had a major failure when it really has not.

A couple of things you may want to consider is that the 991 MT uses a gearbox based on the PDK gearbox. So if you can find MT parts they may be usable in the PDK. Also, there doesn't seem to be anything special about the bearings that I've found, if you open it up you can likely identify a potential replacement. I wish I had more but I just haven't looked at this in detail. You might want to check the third attachment to the post which provides background on the gearing and synchros and may be helpful.

If you have the error codes please post them along with a description of the symptoms. And if you do take it apart please send me photos! Good luck and keep us posted on how it goes.

 

I've been using a PIWIS clone to learn more about the PDK that resulted in some added information to the post. For those interested, this was documented over in another thread (link) that led to some spirited discussion.

Those attempting to DIY a PDK may not have seen that post, so I've reposted some screen shots here. To give an idea of the value in this, here's the PDK's four shift fork engagements as I manually short-shifted from gear 1 to gear 7. These are the real-time shift rod sensor measurements used by the TCU, the legend is on the left of each plot. A negative value means the fork is retracted, positive means it's extended, zero means that particular gear set is in neutral. You can see how the transmission sets up the next gear in anticipation of an upshift as two gears are always engaged (i.e. not reading zero).

This is just a small sample of the potential of this tool, real time plots can also be recorded for the PDK's individual solenoid currents, pressure sensor values, RPM sensors, and temp sensor. This is all stuff the dealer could use to diagnose PDK problems but they don't since it's not called out in their diagnostic flow diagrams. On top of that, mother Porsche won't let them. This info is invaluable for someone genuinely trying to diagnose a PDK problem, and the fact that the dealers don't do it is inexcusable.




Here's a different menu that shows access to the PDK calibration and fill procedure, another user confirmed these procedures are fully functional using the PIWIS clone.

 

Wouldn't it be nice to be able to convert to a manual transmission like one can with BMW's SMG transmission? I'm looking at an E46 M3 with an SMG and it can be converted (all in because pressure plate and flywheel are new in the SMG) for $2200 ... 3rd pedal and all!
As a bonus, there are take off parts from the SMG conversion that are worth a few hundred bucks too if they are in good shape.
So we are talking approximately 1800 all in in my case ... not bad.

 

No

 

I hope folks don't mind but I'm documenting new info I'm coming across in the comments as it might be helpful to others.

Up in comment #66 Hatzenbach posted his fault codes from two separate PDK failures and both were caused by failures of the gear shift rod sensors. In reading posts online, I've seen this same failure come up many times, particularly in early PDKs. I don't think this is a coincidence.

This group of four sensors (which I show the output of in the top plot of comment #94) is located in the gear oil section of the PDKs. 997 and 987 PDKs don't have a gear oil cooler, but Porsche did add a gear oil cooler in 2013 to the 991 and 981s. I suspect this may have been done in response to early PDK warranty failures. The PDK white paper from ZF published in Dec 2008 specifically says a gear oil cooler is not needed and is not planned, so something made them change their minds.

This gear shift rod sensor uses a Hall effect sensor coupled to an electronic circuit that coverts the sensed signal to a pulse width modulation (PWM) output. I don't know the exact sensing component that is used but I suspect it is something like this device. It senses the position of the magnet attached to the shift rod.



This device is made for automotive use but it's only rated up to 125 deg C (257 deg F). I can easily see gear oil temp going above this particularly in a tracked car. Unfortunately the full sensor assembly (which has four individual sensors inside it) isn't available from anyone I can find. Neither Porsche or ZF provide it which is infuriating and probably illegal under consumer protection law. (Update: I did some checking into this as I was going to file a complaint but it looks like it's not illegal unfortunately. Looks like we are on our own.) I contacted the Chinese aftermarket suppliers that I discuss in the post and all were out of stock. The assembly looks like this.





As can be seen, the back side has a black plastic-looking cover that appears removable. I'm thinking these can be repaired by opening them up and directly replacing the Hall effect sensors inside. Many manufacturers including ZF themselves sell Hall effect sensor components like that in the first picture above. I need to get one of the assemblies somehow so I can open it up and figure out the actual component part type in it.

One other thing I wanted to mention is that if the TCU thinks one of these sensors has failed, it shuts off parts of the PDK that have nothing wrong with them. If this sensor fails the TCU responds by turning off the hydraulic pressure for gear selection which leaves the car stuck in the last gear before the failure. So the failure of a $10 part makes the transmission seem like it's completely hosed with some major malfunction. In reality, a simple electronic part failed and the transmission is otherwise fine. However it may make some unsuspecting owner think there's major damage inside (as that's how it seems) and be more willing to shell out $15k to replace the transmission.

 

Interesting point about the addition of the gear oil cooler, and also about components likely being run outside their specifications. Not what you like to see at this level of play. I agree that the right strategy is to take the module apart and do a component-level repair. A bit surprising that it's not potted... not that that would rule out replacing the individual Hall sensors, but it would make it more difficult.

Another motivation for adding the "unnecessary" cooler might have been to allow them to advertise a longer service lifetime for the gear oil.

 

Amazing life saving article! OP, can you please recommend mechanics who would be able to do the job in California?

 

Guys- I ordered a pdk temp sensor repair kit and am having Midwest Eurosport put it in, in less than 2 weeks. I will let you guys know the codes thrown, as well as well as how it does next month my first time at NCM, with NASA.

My fingers are crossed!

Jeff

 

Unfortunately I don't know of any but vaguely remember someone mentioning a shop in West LA (Westside something maybe?) that claimed to offer PDK service. Try googling and I'll see if I can find the reference.

 

Thanks for the update, please keep us posted on how it works out.

 

Hey Cloudspin,

Which exact PDK replacement model are you looking for?

At the time of writing, I see a 9G1300011BX advertised at Sunset for $8K (+ $5.8K core) - https://www.sunsetporscheparts.com/o...on-9g1300011bx

Karl.

 

Thanks. I will be a very happy guy and buy it tomorrow if it is the right flavor. When I search Sunset using my VIN, the only option it returns is over $20k. I will call them in the morning and really appreciate the heads up!

 

Down below in the thread " when it rains it pours, replacing PDK" one of the unlucky mentions having a Porsche dealer installing a factory rebuilt unit with a 2 year guarantee. Only mention this to say someone, somewhere does recondition these units. It's probably not ZF or Porsche but likely some shop in Europe does it under license exclusively. Just saying there are some techs that hold the keys to repair. Somebody is going to have a nice business in the future. Non compete and NDAs are not forever.
I had a similar situation 20 years ago in industry. Italian CNC work center had a liquid cooled electro spindle. Not rebuildable, replacement was $25k. I talked a US company into taking a shot at a rebuild. It worked. $5k. I made the mistake of Sharing this with the Italian mfg. next time the machine went down I didn't have time for a rebuild so had to buy a new electro spindle. It came in a box from my US rebuilder. They had stopped selling new units and were rebuilding old and selling as new. The US rebuilder knew me well and assumed it was a straight up deal, so just sent in their box. Not saying Porsche is doing something like this, just saying rebuilds exist. The source and availability won't be this pricey forever.