does changing the Diff fluid help?

Did you ever find out whats the problem? My 2011 CTT was in for more than total of 3 months (in and out) tried to figure out the rear axle grinding noise problem... Even after Porsche updated the PTV software there still is problem.. However, I have figured out and have deal tested it and now seems to be solved...

If you still have that problem please let me know.

Jack

Hi Jack,

Unfortunately no. I have done the PTV software update recently with no luck. Please let me know how did you fix it.

Hi, you need to have your dealer change the rear differential lubricant. I have my CTT for almost 3 years now (with PTV), with about 52,000km on the odometer. My first noise appeared around 15,000km, took many months in diagnostic and replaced new differential oil at around 22,000km. Noise is gone. At around 40,000km slight noise started to appear again, and Porsche's update software came in and stopped the noise. However, at around 44,000km grinding noise came back and I realized that the new software only make PTV "not" funtioning at 5 km/h or blow, above 10km/h its the same as before...

So, I had another differential oil change at 46,000km, noise is gone again. I guess in my case, PTV is causing fast wear on the oil. Every 20,000km need to change I think is rather ridiculous...

I don't why so little people complain about this, I searched very hard past couple years and never find anyone noticed this problem at all.. Almost give up and sell the thing.. I thought my CTT was a lemon (actually it is, its got tons of problem) until last night I saw your post

hope this helps~

Thanks Jack, I will try changing the diff oil and hopefully it'll fix this.

-Hamad

My dealer finally found the problem in my 2011 CTT. They replaced the “Rear Differential Assembly”
There is also a Tech Bulletin(WM390155) related to thisissue.


After they replaced the differential I have not heard thegrinding noise. You should definitely have this fixed/replaced while it is still under warranty!

With this information, your dealer should be able to replace it without giving you any of the usual BS.

Here is a copy of my invoice you can use to show your dealer what is going on and how they can fix it.

This just cost Porsche a lot of money!!!!

Do all of you with this problem have PTV? It seems that this issue is specific to Turbos with PTV from all of the posts above. Strange.

I have PTV.

Glad to finally find this post. I have noticed this same nasty grind, heavy gearing sensation in our cayenne for past yr or so. Brought it up with my dealer and they were relatively oblivious. Recently porsche posted a rear diff software upgrade which when done to our car helped for few days then problem just got worse. We do have PTV. I just dropped it off again last week and ny dealer brought porsche rep in to evaluate and they are replacing entire rear diff. They sampled my fluid and no metal particles present. I've had two CTT before this never with problem. Hopefully replacement with upgrade will permanently fix problem. Our problem was usually turning left at low speeds.

Hi,

I showed my dealer the internal repair notice number, they didn't say a word and order me a set of new rear diff. Only after 3 years of endless repair back and fourth. However, after they install the new set, the grinding problem is gone, but there is a new problem, driving on straight line when I life gas pedall, the car will swirl to the right. Hit the gas pedal, the car swirl back to straight line. The whole system is f*ed up by the technician. Had enough of it, sold it.

Ordered a 2014 just got delivery 3 weeks ago, what a big difference. My advice, never ever get first model year car anymore.

Oh by the way, changing differential oil fluid last only about 10k km, the noise came back. It's PTV alright, because when technician pull out PTV fuse, everything go back to normal and super smooth again. My new '14 have I ditch PTV, moderate and high speed turn in, mid turn response is different (more push), I miss PTV but I guess no-issue have to deal with is better than grinding noise lol. Oh and this time I added ceramic brake, it's awesome, no more brake dust, really!

UPDATE

Just recently I took my car in for its 60,000km major service. There was a new campaign for the diff system "WD31" which is only applicable for PTV equipped Cayenne's. The previous Software updates (WD03 & WC26) did not help. I have not changed the diff nor its fluid as some of you have done, I just learned to live with it knowing that PTV is causing the noise.
With this new software update, the noise has reduced considerably, it is still there, but not as loud and does not happen as often as before when making turns. I'm very happy that this has helped eliminating (almost) the noise in my case.

Contact your dealer and ask about this software update as this might not be applicable (Campaign #'s etc..) for US-spec cars.

I have a 2010, first year in the UK, CTT with PTV, PDCC & Servotronic and it groans loudly when turning at slow speeds and sounds like I'm dragging the rear sometimes, will fluid changes and software help with these problems, dealer has no idea, can't even hear the noise when out on test drive?

Thanks

Carl

Moving this thread to the new Cayenne Turbo forum with permanent redirect...