Tiptronic conductor plate 996.2 or 722.6

I had some trouble with my Tip going into limp mode on the last track day two days ago. I have the Mercedes 722.6 Tiptronic. Stupidly I cleared the code and didn't write it down. I recall it was something like "second stage turbine sensor implausible reading". After I cleared the code the trans was fine. Last night I drained a little bit of ATF which is darker than I would like, it doesn't smell burnt or have debris in it. It's just much darker than the bright red of new ATF. I refilled the trans, which is not exactly easy. I think I put about 2 ounces of additional ATF in over what I drained out so it was ever so slightly low on fluid. The trans has always acted well for me, it's never shown any signs of slipping in any gear. Also I have an ATF temp gauge and the ATF did not exceed 200F at any time. Normal highway cruising shows 175F or so. This transmission was "repaired" 20k-ish ago, I have no records of what was repaired. The service receipt does say the ATF & filter was changed. I plan to drain and refill the ATF tonight, then next week change the ATF again and replace the filter. It's not possible to drain all the ATF as several quarts hide in the torque converter. That's the reason for the two drain & refill cycles. Making the rash assumption that the conductor plate is getting intermittent and I might change it while I'm changing the filter I checked on the parts availability. So the question, Porsche lists the 722.6 conductor plate as part# 140-270-056-1 which goes through several supercessions and costs over $700. Is there any difference from other 722.6 conductor plates, like the one that FCP Euro lists for $150? I had thought that all 722.6 conductor plates were the same. https://www.fcpeuro.com/products/mer...e-1402700861oe

The Porsche boxed part is the same as any other conductor plate for the 722.6, just with the added Porsche tax. My tranny is (still) at a transmission shop getting rebuilt. The shop had no problem sourcing parts for the 722.6 and did not order anything from Porsche. That goes for fluid too. Pentosin makes tranny fluid for those transmissions without having to pay $39 per liter at the dealer. The conductor plate and wire harness are common failure (or wear) items for the 722.6. From what the tranny shop told me the conductor plate wears or fails and pushes fluid into the wire harness, which then causes electrical faults. In my tranny I had a leak between the front cases (where it connects to the front prop shaft housing (if it was a C4). The shop found one set of clutch plates burnt. Other than the plates they were going to change the conductor plate, harness, new gaskets, refill the torque converter, and call it a day. That transmission has no Porsche markings. It has a plate with the Mercedes part and serial number and the Mercedes logo cast into the case.

Thanks, that's what I thought about the conductor plate. I will probably replace it, when doing a filter change you're already 90% of the way there. The 722.6 trans is also used in most Chrysler cars up to about 2009. In the Chrysler application it calls for Mercon V ATF. Since the internals are the same for Chrysler/Porsche/Jaguar/Mercedes I got some Valvoline Synthetic Dextron III, Mercon V fluid that's specified for the Chrysler & Mercedes application.

I believe it is the pass through connector for the trans that leaks and wicks the fluid into the TCU. Although this may be difficult in the 996, because the TCU is much higher than the transmission ( mounted on the rear deck i believe) the Mercedes TCU is not much higher than the trans and has a shield around the wires that lead into the TCU, it�s easier to contaminate. Either way there�s a newer seal that you can retrofit and it apparently works better. If the fluid is dirty m, keep flushing until it�s clean. Dirty trans fluid is not good for anything.

It should not be possible for the fluid to wick up the harness in the Porsche, there is a second plug under the car adjacent to the shift linkage that would act as a breakpoint. The fluid leak is one of the 722.6 problems, the other 722.6 problem is the so-called conductor plate which has two speed sensors on it that read internal trans speeds. If one of them goes south you are stuck in 2nd gear. The speed sensors are on a flexible cable and sometimes the wires in that flex cable get intermittent. Or that's what I have read. Anyway I ordered a new conductor plate. The part# in the Porsche parts catalog is actually a Mercedes part#: 140-270-05-61 which has been superseded to 140-270-11-61-80. It's not terribly surprising that the trans fluid is dark, it's got 180k probably hard miles on it.