marinerbc

looking through the attached workshop document looks like the root cause might be a combination of material and operating conditions.
as the reverence to the "GNC" coated only parts introduced by Porsche as of August/2018 which is in a simple description " a thermo-chemical process to increase wear resistant and corrosion resistant surface layers. After treatment, the surfaces show a dark grey to black color. Functional surfaces are optimized by: • Increased corrosion resistance • Improved wear resistance • Improved mechanical-dynamic properties. "

the operation condition parts might be due to the potential contamination via the vent .

now maybe part of that dark color "grey/black" oil that was observed by some while changing the TC oil could very much be due to the separation of hardened surfaces , especially when UOA shows abnormal wear in effect.
in light of above i would not use any oil other than Porsche specific for that application for those that out of warranty to reduce the potential of repeat failure. it is just too much uncertainty .

Mike41

Does this mean there should one type fluid for GNC coated and another for non GNC coated transfer cases?

Have their been failures for GNC coated transfer cases in the field yet?

good information!

mike

marinerbc

the short answer to the question of different lubrication requirements depending on method of surface hardening alone is no.
however the duty function of such application requires specific fluid requirements in term of facilitating slippage " torque splitting" especially when software and sensing elements are involved.
https://x-engineer.org/automotive-en...e-awd-systems/

Following Porsche published resolution/recovery process to such events one can not help but to wonder that at one point in their corporate methodologies. evidence/real life test based standards were incorporated,
sorry for going around the long way to explain so please let me elaborate.
My 2016 CTT had a new TC replacement in July/2018 and i am including a screen shot of the iCarSoft control unit information showing the hardware and software part numbers .
they corresponds to what it became official Porsche programming instructions in September/26/2018 titled " The following software update via 'Programming Code' may not be used on vehicles before model year 2015 "
pages 8-9 of 10 in the attached Porsche workshop TB.

Mine by the way does not look like it got the GNC coated plates " reinforced type" , i am just judging by the software version being the 1010 and not the 1050 " page 3 " and the built date of October /2017.


So in short, adding friction modifiers and or using other lubricants than Porsche specific will introduce more variables in this highly complex, sensitive and critical component, or at least is a risky proposition i am personally not willing to take in my situation.

see post # 8
https://rennlist.com/forums/cayenne-...rim-range.html

porscheconvert

15k miles later and 2nd tc failure. 2015 diesel

deilenberger

Diesel failures are quite rare. Any particular reason you might have two failures? Towing near max limit? Fording deep streams?

porscheconvert

No towing...just regular driving

mmurph318

Purchased a 2014 GTS with 80k. I was aware of tc issue. Upon inspection, everything checked out okay. Unfortunately, after 3-4 k I starting noticing the juddering in shifts. Thanks to all the contributors on this forum, I didn’t panic, but instead did the fluid change. I used the Ravenol and a friction modifier (about 2.5 fl. oz). As others have reported, the symptoms were gone right away. I have put a 500 mi on the car since. I added to the google form and will update as I add more miles.

JSteve

The Transfer Case on our 2016 Base was replaced this week under warranty at 48K.

We are 5 hours from the closest dealer. On Wednesday the dealer sent a driver with a 2018 Macan loaner to get our Cayenne. They returned our vehicle Friday. All symptoms are gone. The vehicle is much quieter.

The service invoice says, "...followed ATI3965-1101. Disconnected wire connector to transfer case and all symptoms disappeared. 39651920 2.63 Installed Porsche exchange transfer case and updated vent hose."

A few months earlier the Service Manager told me that transfer case failure was a problem on the Cayennes, and that ours would eventually need to be replaced. Before this repair he told me that the replacement case was a different part number than the original. He was confident this replacement would fix the problem.

I did complete the survey--I also had completed it a few months ago before we had problems.

Speedvagen

Transfer Case replaced last week at 42k miles on my Turbo. Survey completed.

1BadAction

My local Service manager agrees on both counts, it's an extremely common issue, but once it's fixed the problem hasn't reoccurred on any he's done. They do 2-3 a week and gave me a set price (which was VERY reasonable) for replacement out of warranty, since I may or may not buy a CPO Turbo S within the next few weeks.

deilenberger

Thanks!

docdrs

My wife started noticing the shudder again, I could too a bit but I don’t drive her cayenne much. Replaced porsche fluid and FM and it’s fine again. 148,000 Km’s. This is the third fluid change so I’m thinking it should be about a 30,000 km interval or every 2 years.

rbaye1123

when i purchased it 2 years ago with an extended warranty
and when i drove for around 3 months i noticed strange gear shifting happening especially when i had heat up in the car so i troubleshoot by cranking up the heat and erratic gear shift started again
so i went to the porsche dealership and at first they said it was a transmission and then they discarded that hypothesis and got me a reprogrammed, remastered transfercase for 7k which was covered by the warranty
but gasket leak wasn'r covered so i ended up paying 2.3k for the whole services.
After that i took it to the porsche vintage shop in bellevue WA for plugs, coils, serpentine, water pump replaced as well as bleed out all the liquid
beeen drining it good ever since.

DAVfoto

Completed from my end as mine was replaced just before me purchasing the car back in January. They did the week prior.

I will start doing changes every 10-15k miles or so to make sure this case lasts.

cbracerx

Completed survey. My new to me 2011 with 38K miles had minor but detectable shifting vibration. Changing fluid resolved the issue, but I did buy all the rebuild parts for the day when that will be needed.