Update as of 05/02/17

 

Looking at the data - more than 50% of the reported failures were to CTTs and a CTTS. that's disproportionate considering the CTT was probably one of the lower sales number Cayennes. Certainly the V6 base model well outsells all the other models, yet it's represented by a significantly small percentage of failures.

Looking at that - would lead me to believe the TORQUE passing through the transfer-case has a direct bearing on the likelihood of failure. Looking a bit further into the numbers - the CTT's that had their fluid changed ALL recovered normal operation. Looking at the failure mileage - with two exceptions - all of the CTT(S) failures were with more than 50,000 miles.

That leads me to an educated guess (WAG really) - that the fluid is being damaged over time - and the failure occurs more frequently in transfer-cases that experience high torque applications. This all sort of makes sense. The clutches DO slip, and have to proportion the torque between the front/rear axles. The force they slip with will increase with increasing torque - and this will result in more localized heating of the clutch disks, which are cooled by the transfer case oil.

That also explains the repeated mention of a "burned smell" on cases where the oil has been changed.

It reinforces my suggestion that the oil be changed at regular intervals. I'd suggest right now - looking at the failure frequency - every other oil change should be adequate - unless your Cayenne is being used in high-slip situations (off-road, mud, snow.) In that case more frequent changes may be beneficial.

That's it for now. I'm always interested in more data - so if you've had a transfer-case issue - please do report it.

 

Thanks Don! As soon as the Porsche OEM oil was delivered, I changed it today.

2012 Cayenne V6, 62,500 miles

I used the new Porsche OEM Transfer Case Oil (# ending with 63).

As shown in the attached photos, the old TC oil is very dark. You can compare the old TC oil color with new one. No small metal debris in old oil was found. I didn't have any specific symptoms associated with TC but I thought that replacing oil is very effective insurance. From time to time, I used to hear "glick glick glick" from the passenger side at a low speed but I didn't hear the noises any longer during test drive. I am not sure if it's related to tonight's TC oil replacement. I will update if it returns.

The torque for fill and drain bolts was 13 ft-lb.

Hopefully it helps. Thanks again for those who uploaded great info. Many special thanks to Don!!!

 

That's pretty much what mine looked like. The only thing that can make it that dark is clutch wear and perhaps overheating of the oil. Thing is - the wear particles from the clutch are likely to alter the gripping of the clutch plates - which is probably what's happening when the transfer case becomes grabby.

Every other oil change I think for a service interval..

 

Are you saying 20K then factory OCI???

 

Since the factory OCI is 10k - 2x 10k = every 20k. That could be adjusted based on how dark the fluid coming out after 20k miles is.

 

Hi Steph,

I don't know if you still need an OC indy shop recco, but I've used Hans Imports since 1975 (Hans is a former Circle Porsche Tech), & he has several customers with the Cayenne/Touareg/Audi Q7 trio.

If you're a PCA-OCR member, then just look in your monthly "Pando" magazine copy for Cape Auto, Bill Brewster (San Clemente) & one or 2 other good Porsche shops.

If you're not a member (yet), then come out to Original Mike's in Santa Ana this Saturday morning 8-10 for the Club Breakfast, or Porsches & Pancakes same time at Woody's in Newport Beach to meet some folks, consider joining, & at least pick up a sample of Pando for your time & future reference.

Aside from club activities, PCA membership is only $46/yr for you & another "Associate" - plus you'll get both the local Pando & the national Panorama magazine (membership is less $ than a subscription to Excellence magazine alone, & Pano is now better IMHO), plus many of the member Indy shops & Porsche Dealers give PCA members a 10-20% +/- discount on parts & services & some special offers too.

No, I'm not the membership person, but someone will be there to help you & answer any questions.

Hope this helps!
Tom
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Add Sunset Porsche up in Portland OR to that list of Suncoast in FL & Sonnen in NoCal, to your list of Porsche dealers with good parts pricing.

I've never heard that Sonnen is, but will defer to your experience.

Cheers!
Tom
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Okay, so ONE MORE dang thing to look out for in the 958 Cayenne S we're on the hunt for (as well as 957), since we want to tow with ours.

1a - So what can I do to test for the dreaded XC problem in a test drive?

1b - What will I feel & hear to tell me that there's a problem?

1c - ... then what to check in more depth with any I take to a full PPI?

I ask this cuz I know that even the commonly flaunted 114 point checklist for a Porsche CPO will NOT cover either this or the dreaded Cam Adjuster bolt problem.

2 - Would our using the CS mostly or 50% of the expected 3-5000+/- mi/yr in towing either our 3000-3500 lb vintage Avion T20 (low, light & streamlined aluminum like Airstream), & my 73 914-2.0 on a flat open or closed car carrier translate to the higher TQ use that Don is postulating being the cause of this XC failure??

3 - So would it be a safe assumption to say that the earlier 2008-10 957 CS Xfer Case would be more sturdy? .... especially for towing?

BTW - I think probably OCI at 3-5000 mi & the XC+2xDiff+Trans+Coolant+Brakes at 5-10,000 miles - or annually & biannually respectively regardless of miles - is a better plan, than the longer Porsche intervals.

TIA -
Tom
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Jeeze, numbered and even sub-sectioned questions. You really know how to get a guy to answer Tom..

So as best I can..

Drive a lot of different ones - and if one feels less smooth on acceleration, especially during 2-3 shift and 3-4 shift, add in the cost of a new transfer case to the bargaining (although it probably just needs the oil changed.)Not smooth. I hesitate to say roughness - but if it feels a bit lumpy when accelerating - that's a clue. If you hear noise, especially on turning - that's another clue (difference in speed of front/rear wheels causes the clutch to work harder.) Clicking noise if often mentioned.Have them pull the top plug on the transfer case and look at a sample of the oil. If it's REALLY black and burned smelling - something is likely going on.Since I was postulating it - yes. Hauling the trailer will require additional torque on acceleration, and that torque goes through the transfer case. There is a reason Porsche has a calculation that gives a number for the power that has gone through the TC. More power = more wear = more likely the fluid is contaminated or kaput.Entirely possible. But since it's about the only instance I can think of where they might be superior to the 958 series - I'd hesitate to buy one just because it won't need a transfer case fluid replacement as quickly.3,000 miles = excessive oil changes. That's from back in dino based oil days. ANY synthetic is good for 6,000 miles, and most considerably longer than that. To really tell - have Blackstone test it and let them tell you when you should be changing itLater - HTH..

 

Thanx for the info Don.

You should've seen my exams when I was teaching at UC Irvine!

I'd suggested the shorter time spans for fluids due to the heat & particulates which harder any working vehicle will do in towing, AX or tracked, or a very heavy right foot, etc. - vs. long leisurely cruises, grocery getting & Soccer parent - or Lacrosse, Rugby, etc.

I'm telling you, these QC & design issues with Porsche - & their recalcitrance in standing behind their products - are fast souring me on the Cayenne s for us!

Maybe we should consider a Toyota Sequoyah if we can make it work for our tight driveway & street, & if the ride isn't hard for us old folks, & if my wife will be comfortable driving it.

PS - Thanx again for your work on this XC issue, & the cam adjuster bolts issue!

Cheers!
Tom
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After I replaced TC oil, I carefully checked several kinds of driving conditions because I didn't want to end up with "placebo effect" However, I am concluding that it's not a placebo effect but a real improvement by simply replacing the burnt TC oil. Don, please add my result to the updates.

Since I got a great result, I have been motivated to replace front & rear differential fluids as well.

http://www.pelicanparts.com/catalog/...pg3.htm#item12

In the above link, Castrol Syntrax Longlife 75W-90 is the Porsche OEM differential fluids. So I am going to use this.

Now my dilemma is that I must figure out how to lift my Cayenne for differential fluid change.

I never completely lifted my Cayenne on all four jack stands.

Can I use "RhinoRamps" for the front wheels and "Jack Stands" for the rear wheels? Any recommendation and/or web links for lifting Cayenne safely?

Thanks in advance!

 

Yes, so long as your ramps aren't so tall as to set the vehicle at a wonky angle for jacking.

Yup - one big one! Never - ever - NEVER use the dangerous ratchet type jack stands!!!!

They can slip off the ratchet too easily on it's own or when accidentally bumped. I personally know of 2 folks killed & many severely injured with these crappy jack stands - & one killed was by a relatively light 914/4 (+/- 2100 lbs)!

So throw away the crap ratchet ones, & get some proper weight rated pin-lock jack stands folks!

Be Safe!
Tom
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Be happy to - but need some info, like year/mileage/model/oil-used. Burned smell?

Glad to hear it worked for you. We continue with 100% success so far.

 

+1

when I'm not using my lift, I use either Jackpoint stands, which are awesome as they allow you to Jack and support from the same point (but are sometimes a little low), or esco stands which use the pin through the post method and can go really high. I'm not sure of the weight rating on the escort stands but would check that before using them on a Cayenne.


Escos are the tall ones supporting the sides of the motor