jsoderbe

Hi, I have a 2014 Cayenne S Diesel, with the massive 4.2 TDI engine. Tuned by me to 464 Hp and 1000 Nm. It is just awesome, the power is addicting... but I have already replaced one front diff, and the prop shafts are beginning to show signs of wear.

So of course I drove too fast and lost my drivers license just before christmas, leaving the car parked for more than 2 months without anyone touching it. When I got my license back I noticed a shudder that got stronger over the coming weeks, until I couldnt really drive it anymore. It was so bad that I had to ease off from the traffic lights, and the car vibrated so bad I realized I needed to do something.

I started reading up on the issues here, and learnt that I actually could repair the TC instead of buying a new one. That was good news considering the S Diesel transmissions are rare on the junk yards, meaning very expensive. And besides that a used TC is always a risk.

The diesel models have another TC than the gas versions, and when I read more very few diesel owners had issues. Also a lot of members here reported improvements after they replaced the TC fluid, so I decided to give that a try this last weekend.

The Porsche stuff is incredibly expensive with 70 USD/quart. So I bought it and went to a friends shop, and spent 15 minutes replacing the fluid. The stuff that came out was totally black and watery! In vent crystal clear new Porsche fluid.

After driving 250 miles I am happy to report that the shuddering is GONE! The transmission shifts better than ever! It always had a funy shift from 3rd to 4th, but even that is gone.

I wanted to share this story to motivate every cayenne owner to replace the TC fluid earlier than the 150k miles Porsche say. It is a very inexpensive service, and could potenially save the owner a $5-10k repair.

Regards,

Johan

Mike Murphy

Is the TC fluid the same fluid that’s in the transmission?

Quadcammer

No, atf in trans, more like very thin gear oil for tc. Both have a correct spec

Mike Murphy

Ok, so why would the vehicle shift smoother after the TC fluid change?

Quadcammer

My take is that it relates to how power is applied upon gear change. Ad the torque is applied to the tc clutches, if the fluid is crappy, they tend to either slip or be quite grabby, resulting in odd hesitations, shuddering, or harsh shifts

cbracerx

Transfer case issues can absolutely present like a bad shifting transmission, or like a slippery/bumpy road surface. Glad to hear the fluid cured it! Now get on an every 20K mile (or less) change cycle.