'11 Porsche Cayenne S Transfer Case Issues

[Imcoz]

For those who may care, I wanted to share my experience owning my 2011 Porsche Cayenne S. More specifically, I wanted to share my experience with an issue this model seems to have, but is not talked about too much on the forums. That issue is the all-wheel-drive transfer case(TC) failing. I've heard that its prevalent with earlier 955 & 957 as well as on other later 958.1 models. Still, not a lot of information out there.



I purchased my '11 Cayenne S in Florida as a CPO car with about 30k on the clock. We had it shipped to Northern NJ where snow and ice are now a factor and although I don't drive the vehicle in very challenging slippery conditions, I do tow a race car trailer about half a dozen times a year.

Last December '15 (about a year after buying it) I experienced a chattering feel or chugging feel upon accelerating in 1st through 4th gears, typically after the drivetrain is warm and while starting from a traffic light or in heavy traffic. I'd read about this a tiny bit, and after a test drive with my local dealer mechanic, it was confirmed... we didn't even make it out of the dealer lot and the mechanic seemed pretty convinced of the issue. What's interesting is this issue doesn't through any codes. The mechanic said "I'd be lying if I said we didn't replace a bunch of these transfer cases."

My Porsche CPO warranty was fully in effect and covered the repair to the tune of ~$6k, what would have bee a pretty major expense. My concern was always that the same faulty part had been installed, I could never get a straight answer on whether Porsche was fully aware of the issue and had an updated component. My question has been answered just this past week, when the same symptoms popped up again and we made a beeline to the dealer to have it checked out... same mechanic, same comment; "I'd be lying if..." Luckily my concerns over the last fix convinced me to purchase a Porsche dealer sold Fidelity extended warranty at the end of the CPO term. I pressed the Service Manager(SM) and the Mechanic on the cause and whether Porsche has improved the part. The SM gave me a long answer about it being the combination of the electronics and the case itself, something like "the electronics sense slight differences from all corners of the wheels/traction and tend to beat up the case sending power to the different corners..." interesting. The mechanic says a newer TC has been issued and that he'd be very surprised if the issue occurred again.

So, now the Pepper has been tucked away at the dealer for the last week awaiting an adjuster from Fidelity to confirm the repair. Assuming it's covered, which I believe it will be, this will be the third TC since the car was new.

I'll update this post soon, but would definitely like to hear of any other experiences out there. Who know's, it may come in handy as others confront this issue. We all love this brand or there wouldn't be this great forum it weren't for the Porsche Love.

[Fredn5]

Imcoz,
Yes, this is a very common problem especially in first generation e2 cayennes such as your '11. Unfortunately, when replaced on the dealer level the most we're allowed to do is drain the oil and inspect for metal particles, then the core must be returned unopened. I've found that the Cayennes with the most problems generally have mismatched tires or unevenly worn tires especially front to back. I always recommend keeping your tires tread depths within 30% of each other, too many times a customer gets a nail and replaces only the one tire, causing an uneven condition, causing more wear on their transfer case. I believe the problem to be an oil lubrication/cooling issue, especially since the problem is most common after the drivetrain is warm. These transfer cases do not have an additional oil pump like most common domestic transfer cases on trucks that can tow, they're more closely related to their Volkswagen counterparts transfer cases which are not built to tow. This is to reduce drag and improve fuel economy, unlike a domestic truck which can be switched out of 4wd and is a fuel hog when in 4wd.

Additionally, it may be worth taking a ride with a tester and monitoring the wheel speed values. The wheel speed sensors are a direct input to the PTM and there is an updated part for them (all four replaced at same time). I have had a case where the front two sensors were becoming lazy, meaning they were slower, displaying slower speeds than the rear. This would cause the PTM to think the rears were slipping, creating harsh shifting and chugging, especially when warm.

And in close, always make sure your towing weight is not greater than Porsches recommended value, which is about 3.5t for tiptronics.

[Imcoz]

Thanks Fredn5! Good info here. As an update, after my last replacement TC I change all four tires for new and been very careful keeping and eye on wear and pressures. At this time the Cayenne is shifting hard and chugging again... here we go! This will be the third TC for this ride.