Presto

I dropped my engine and tranny to trace an oil leak. Found out its leaking from some sort of vent valve on the top of the PDK transmission.

Can anyone shed some light on what exactly this is or how its leaking? Could it be the PDK clutch fluid was overfilled? Or the differential fluid (automatic transmission fluid)?

Pics attached
https://imgur.com/a/RFpLCvq

Update: It was the diff fluid which was overfilled. Drained it and filled the correct amount and no leaks since.

docdrs

I think its almost impossible to overfill the clutch fluid as you need a piwis to get the last .5 litres in. So it must be the gear oil. how many miles on the car and was the gear oil ever changed? You would think there would be more oil around the vent

Presto

After taking a look at the below PDK diagram, it definitely looks like its the gear oil (mobilube ptx 3.12 quarts factory fill) and not the pdk fluid. 51k miles, Not sure if previous owner changed the gear oil.

I drained it and filled 2.85 quarts (car on flat surface, pumped oil in till it started leaking out of fill hole) now just to be on the safe side.

docdrs

not 100% sure , but I think you want the car running, run it thru each gear for 10 secs, put in park running , then fill again till comes out to get proper amount. Did you open the fill hole first ?and did any come out before your drained?

Presto

Yes fill hole opened first. Nothing came out probably because everything leaked out of that vent valve up top.
Oil residue all over underbody components, the plastic undertray cover and transmission housing.
Will be spending quite sometime cleaning it all.

Service manual does not mention to start car and run thru gears for this fluid. That's only for pdk clutch fluid while monitoring temperature etc.
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docdrs

Presto

Asked around and pretty much no one seems to know why the oil would leak from the top. So I just cleaned it all up. Made sure the fluid was not overfilled.
it is also nearing the pdk clutch fluid and filter change mileage. So that will be done soon.

sandwedge

Is your car under warranty? Pretty sure you know why I'm asking.

Presto

Haha warranty . If I had warranty I would not have paid an indy to drop engine and gearbox.
Anyway whenever I figure out how to stop leak or fix this I'll come back and report. Maybe it will help others.

docdrs

Presto

sandwedge

Hope you figure it out. And of course it will help others. As you probably know, not even the dealers, never mind indys know much if anything about what to do with PDK issues so it's outright replacement more often than not whenever there's a problem. It's got nothing to do with lack of skill or capability but has everything to do with Porsche's refusal to share the information and guidance needed. Never heard a good explanation for this behavior so it's all about what's more profitable for Porsche. Why provide Porsche techs around the world with the tools and information needed to take the PDK apart and fix them when you can instead leave the owner of the car with no choice but to replace the whole unit for around $12K?

voiceprint1

Also curious why no shop has dove in and become a PDK repair expert? I assume the manufacturer of the PDK must be able to repair them if they build them?

Wayne Smith

I suspect of you divide the number of out of warranty PDK repairs by the number of shops in the country there hasn't been much incentive by any individual shop to invest the required time.

voiceprint1

I agree, but there seems to be an expert for every other aspect of the car, there is a 20 page thread on replacing climate control ***** spanning years. It seems weird on such a performance oriented car everyone just threw up their hands?