[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.