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Massive Porsche X-fer case failures #4470963
07/26/17 12:16 PM
07/26/17 12:16 PM
Joined: Jul 2017
Posts: 4
Texas
GKoenig Offline OP
GKoenig  Offline OP
Joined: Jul 2017
Posts: 4
Texas
I recently bought a new 2016 Porsche Cayenne V6. It developed a very bad off-idle hesitation at 11k miles, turns out it was the x-fer case slipping and the computer was trying to adjust for it. I quickly discovered that virtually every x-fer case built from 2008 has had reliability issues and the only TSB/fix so far was to install an extended case vent tube from the undercarriage to the engine bay. Supposedly this helps prevent water and dirt from getting into the case. Porsche seems to be very good about replacing the entire case without much trouble but it appears that it is either a poor design, materials, or lubrication, must likely all 3.
The design uses a wet clutch pack to vary the full-time AWD torque between front and back. BMW x-drive uses the same technology, however, they use sensors to monitor the oil and clutch pack wear and provide a warning when the oil needs to be changed.
Porsche recommends that the x-fer case oil be changed at 90k miles. Obviously this is a problem. Many owners have resorted to changing their own x-fer case oil between 5k-20k miles to be proactive. The results are shared online and the majority of the complaints are "burned oil" - that is, very dark color with a very "burnt smell".
The Porsche recommendation for the case oil is ESSO LT 71141(formerly Italian, now Mobil 1):
cSt @ 40 C 37.2
cSt @ 100C 7.4
Viscosity Index, ASTM D 2270 168
Density @15 C g/ml, ASTM D 4052 0.855
FP 219 deg. cel.

Many are sticking with the OEM oil and just changing it regularly. BMW oil is also ESSO LT71141 with a BMW OEM label.

I would like to find the best alternative oil to use as I believe there are much better oils now since the ESSO spec was adopted many years ago.

Since the clutch pack is "wet", the oil plays a critical role in its reliability, performance, and efficiency. The clutch is slipping by design which creates a tremendous amount of heat. Is the flash point of a viable ATF fluid a good indicator of a suitable replacement? If so, Amsoil looks to have a good product.
How about viscosity? Since the clutch is designed to slip, viscosity will heavily influence performance?

Regardless, the oil is being cooked by friction rather than contamination from moisture and dirt.

I have researched 12 different ATF oils and can not determine which specifications would suit this application. It is a transfer case, not a transmission and therefore will have completely different requirements for oil. Why would it not require something similar to a limited slip rear differential oil as it also has a slipping clutch design?

Perhaps we will require a cold weather oil and a hot weather oil?

Is there an additive that would help with the heat?

Thanks in advance!


Last edited by GKoenig; 07/26/17 12:20 PM.

2016 Porsche Cayenne V6 - with garbage x-fer case
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4470974
07/26/17 12:29 PM
07/26/17 12:29 PM
Joined: Dec 2015
Posts: 261
Ontario Canada
Canadastang Offline
Canadastang  Offline
Joined: Dec 2015
Posts: 261
Ontario Canada
That's a tough one.

The viscosity at 100C is very close to say a Mercon V.

I'd be tempted to try Valvoline MaxLife ATF or perhaps even royal purple synchromax (syncromax is manual trans fluid for applications that require ATF).

Another dedicated transfer case fluid is Motorcraft XL12.

I think the t-case would benefit from some extra friction modifiers to reduce friction and heat. Just my .02

Of course, use all these at your own risk, since they're "not approved."

Re: Massive Porsche X-fer case failures [Re: GKoenig] #4470987
07/26/17 12:39 PM
07/26/17 12:39 PM
Joined: Jul 2017
Posts: 4
Texas
GKoenig Offline OP
GKoenig  Offline OP
Joined: Jul 2017
Posts: 4
Texas
Thanks for the response, and you bring up another point, oil manufacturers list "LT71141" compliance, not "Porsche" approved compliance.

My rig has 11k miles and the case was just replaced, as have thousands of others, I have no hope of keeping this P.O.S. over the long haul, but changing the oil is a snap, plus its less than a quart.


2016 Porsche Cayenne V6 - with garbage x-fer case
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4470995
07/26/17 12:52 PM
07/26/17 12:52 PM
Joined: Aug 2008
Posts: 3,167
USA
Reddy45 Offline
Reddy45  Offline
Joined: Aug 2008
Posts: 3,167
USA
So it's a transfer case that works full time, and uses wet clutches to vary torque, but is running on basically automatic transmission fluid?

ATF in a transmission typically lasts a decent number of miles because it is cooled via the car's existing cooling system.

I would imagine that is not the situation for your transfer case, and I bet the actual fluid volume in there is low and that provides less of a buffer against heat.

Since you are still under warranty, I would stick with the mfr recommended fluids, but is there any way to improve the cooling for the transfer case?

Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471009
07/26/17 01:10 PM
07/26/17 01:10 PM
Joined: Dec 2015
Posts: 261
Ontario Canada
Canadastang Offline
Canadastang  Offline
Joined: Dec 2015
Posts: 261
Ontario Canada
Originally Posted By: GKoenig
Thanks for the response, and you bring up another point, oil manufacturers list "LT71141" compliance, not "Porsche" approved compliance.


It's pretty rare to see an 'approved' oil unless it's OE branded oil. Usually it's 'meets specifications of' or something to that effect.

I wonder what that repair bill would cost out of warranty.

Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471011
07/26/17 01:11 PM
07/26/17 01:11 PM
Joined: Jul 2017
Posts: 4
Texas
GKoenig Offline OP
GKoenig  Offline OP
Joined: Jul 2017
Posts: 4
Texas
I think they added a plastic air scoop to the bottom as well, I will look at this too, good tip.

I would think that I could get away with putting anything in there since there is a known issue and replacement is commonplace.

I plan to try a new oil and see how it effects performance, I may know within a few hundred miles if the viscosity is doable or not. If performance appears to be unchanged, I will drain it at 1k mile intervals to have a look. There has got to be a better oil than what they are using.

$5k roughly to have it done outside of warranty, they do not appear to be fixing the clutch but rather replacing the entire unit.

Porsche seems to be "blessing" Mobile 1 oils right now. Motul is popular with the small shops. They want $55 for a quart of OEM t-case oil at dealer.

So far, I am leaning towards Amsoil ATF as its viscosity is closest to ESSO with a much higher FP -> 235 vs. 219

Last edited by GKoenig; 07/26/17 01:19 PM.

2016 Porsche Cayenne V6 - with garbage x-fer case
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471017
07/26/17 01:19 PM
07/26/17 01:19 PM
Joined: Sep 2004
Posts: 7,530
Marshfield , MA
andyd Offline
andyd  Offline
Joined: Sep 2004
Posts: 7,530
Marshfield , MA
What is so darn hard about building a reliable TCase? Yah, I know it is an antique, But the New Process 219 229 etc T Cases used a viscous coupling. In 20 yrs of GWags , no failures, and I broke just about everything else. Just curious, did this engineering marvel have a low range, like a real SUV?


'16 Camry LE STP synth 0w20 and STP filter. the Fridge

1994 Ranger ,the Rat, 5w30 dino, STP filter

'16 Camry SE, Valvoline HM 0w20 and OEM filter
Thick oil is better grin2
Re: Massive Porsche X-fer case failures [Re: andyd] #4471027
07/26/17 01:27 PM
07/26/17 01:27 PM
Joined: Jul 2017
Posts: 4
Texas
GKoenig Offline OP
GKoenig  Offline OP
Joined: Jul 2017
Posts: 4
Texas
Negative on the low range, this is soccer-mom performance brutha! blush


2016 Porsche Cayenne V6 - with garbage x-fer case
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471071
07/26/17 02:18 PM
07/26/17 02:18 PM
Joined: Aug 2004
Posts: 1,467
San Antonio, Texas
sasilverbullet Offline
sasilverbullet  Offline
Joined: Aug 2004
Posts: 1,467
San Antonio, Texas
If the car is still under warranty you could be asking for the wrath of Porsche not honoring it if you don't use what they say. Be carefull...


03 Porsche 911 Liqui Moly Leichtlauf High Tech 5w-40 & Mahle filter
14 Honda Accord 4dr EX-L 4cyl-M1 0W-20 & WIX XP
02 Chevy 5.7L van-GTX HM 10W-40 & WIX filter
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471137
07/26/17 03:41 PM
07/26/17 03:41 PM
Joined: Apr 2010
Posts: 13,534
Chicago, IL
dparm Offline
dparm  Offline
Joined: Apr 2010
Posts: 13,534
Chicago, IL
I'm hoping MolaKule can chime in here...


2017 Chevrolet Corvette Grand Sport
Re: Massive Porsche X-fer case failures [Re: dparm] #4471261
07/26/17 06:07 PM
07/26/17 06:07 PM
Joined: Nov 2005
Posts: 3,229
FL
mcrn Offline
mcrn  Offline
Joined: Nov 2005
Posts: 3,229
FL
Originally Posted By: dparm
I'm hoping MolaKule can chime in here...




lol thats what im hoping for as well.


2012 Nissan Rogue
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471320
07/26/17 07:22 PM
07/26/17 07:22 PM
Joined: Sep 2015
Posts: 2,260
Malaysia
zeng Offline
zeng  Offline
Joined: Sep 2015
Posts: 2,260
Malaysia
It's a design problem in minimal lubricant volume for cooling, hence providing minimal margin of safety as in thin vs thick debate.

Re: Massive Porsche X-fer case failures [Re: GKoenig] #4471893
07/27/17 11:33 AM
07/27/17 11:33 AM
Joined: Jun 2015
Posts: 66
VA, US
SoNic67 Offline
SoNic67  Offline
Joined: Jun 2015
Posts: 66
VA, US
I would use a Synthetic oil with the closest viscosity to the OE spec, Mobil1 or Amsoil.
Extra cooling is essential, like the air scoop.
Also, keep the wheels inflated equally and rotated very often. Of course, they have to be identical. 1/16" difference in diameter can add heat.

PS: The AWD that uses a vascous coupler (Borg Warner) is based on a different mechanism, no cluches inside that one. That's what the AWD Ford Explorer had in their V8.
PPS: For who asked about a Hi-Lo range changer. Those 4x4 TC are not AWD, an AWD is basically a true differential with some kind of limited slip. They stay engaged all the time.

Last edited by SoNic67; 07/27/17 11:40 AM.
Re: Massive Porsche X-fer case failures [Re: SoNic67] #4472120
07/27/17 03:31 PM
07/27/17 03:31 PM
Joined: May 2008
Posts: 2,016
NJ
UG_Passat Offline
UG_Passat  Offline
Joined: May 2008
Posts: 2,016
NJ
Originally Posted By: SoNic67
I would use a Synthetic oil with the closest viscosity to the OE spec, Mobil1 or Amsoil.
Extra cooling is essential, like the air scoop.
Also, keep the wheels inflated equally and rotated very often. Of course, they have to be identical. 1/16" difference in diameter can add heat.

PS: The AWD that uses a vascous coupler (Borg Warner) is based on a different mechanism, no cluches inside that one. That's what the AWD Ford Explorer had in their V8.
PPS: For who asked about a Hi-Lo range changer. Those 4x4 TC are not AWD, an AWD is basically a true differential with some kind of limited slip. They stay engaged all the time.


There are exceptions to that rule in your PPS.
VW 4XMotion on the Touareg is a AWD car with a Borg Warner Transfer Case. It uses a Torsen center differential to provided the AWD capability.
The Toyota Landcruiser J100 has a similar type of system before the Touareg got it, AWD with transfer case.


2016 VW Tiguan|APR Stage 1|Neuspeed P-Flo|Osram CBI|Redline 5w30
Re: Massive Porsche X-fer case failures [Re: GKoenig] #4472359
07/27/17 08:12 PM
07/27/17 08:12 PM
Joined: Jan 2009
Posts: 1,306
Watertown, New York
cronk Offline
cronk  Offline
Joined: Jan 2009
Posts: 1,306
Watertown, New York
The VW Tourag is built on the same platform as the Porsche Cayenne, do they use the same transfer case?


2008 Ford F350
2003 Chevy Cavalier
2011 Nissan Quest
1986 Pontiac Trans Am
1940 Ford 9N Tractor
Amsoil lubes and filters!
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