scott40

My buddy’s 981 CS is having a PDK issue. Suddenly the system is up shifting in places it shouldn’t be. It’s upshifting from 2nd to 4th coming out of turn 1 at VIR. Tried to reset it. Tried manual mode- car was in 2nd and shifted itself into 6th. Definitely not normal behavior. Anyone experience something similar?

tcsracing1

might need porsche to plug into it. Could be as simple as a software upgrade.

scott40

It began leaking PDK fluid at the end of the weekend so guessing it will need a rebuild. Surprising his car only has 11k miles. Luckily now you can do a rebuild.

sonorous

A rebuild is the easy button, although a costly one. A leak and weird shifting itself however does not have only one solution. I had a fairly bad leak and weird shifting on my 981 at the 4-5k miles range. Mine was failing to shift, stuck in gear, and throwing transmission codes. It was finally diagnosed by a competent shop as a differential seal leak inside the transmission. That repair was reasonable and has held strong for a full year with zero issues. The PDK has regular gear oil in the gearbox side and pressurized hydraulic ATF fluid in the clutch pack side. If the ATF leaks into the gear oil it messes up the viscosity throwing off the shifts and pushes oil out of the overflow. YMMV

scott40

We change PDK fluid annually and diff fluid every 3rd event.

tcsracing1

11k miles and leaking. Yup, rebuild time.

BGB is doing PDK rebuilds now.

t-design

Atlanta Speedwerks doing rebuilds too.

jbaker136

I believe what BGB is doing is shipping them out to ZF in Germany under the Clubsport PDK repair arrangement that PMNA recently announced. The prices from PMNA are much less then going to a local US based rebuilder such as Atlanta Speedworks. These PDKs are not that complicated so you may be able to find a local shop willing to try and sort out the issue. There is a huge thread on PDK repairs on Rennlist in the 997 forum. I suggest giving that a look.

Guide to Repairing a PDK Transmission - Rennlist - Porsche Discussion Forums

Jeff

jbaker136

All good points. One thing worth adding. On the street version of the PDK, there is an open vent at the top of the housing and fluid will come out this vent for reasons such as the one you mentioned, if it is overfilled, at tracks with a lot of lateral g-forces, or when the gear oil gets hot (more common with LSD). However, on the PDK in a Clubsport, this vent is not open but connected to a vent tube and recovery reservoir so you should never see a leak on a Clubsport PDK coming from the top of the transmission where the vent is. There are a few other areas where the gear oil or PDK fluid can leak out by design when a seal fails. Bottom line, all of these are repairable and hopefully as work gets out that these PDKs are nothing magical, the price and availability of repair options will become increasingly accessible.

Jeff