I've been quoted £2300 ($3000) for a new Transfer case for my 2012 CTT. Is it even worth opening up the old unit to try and have it repaired?

 

Really questionable since I suspect it's darn near impossible to find an independent who has any experience at all working on Cayenne transfer cases.

The learning would be done on yours - making the lesson rather expensive for you. Dealers won't touch them since they don't want to warranty repairs like that (and Porsche requires them to..) They want something they can install and forget-about - or bill back the R&R labor to Porsche if the sealed unit does fail. The factory manual basically tells how to replace a failed one - not how to rebuild it. So data essential to rebuilding one isn't available.

 

Great point!

 

good advice. I spoke to the tech and he said it would be a first effort for him. Going to go with the new unit. Thanks

 

My 2012 Cayenne S with 50k just had similar issue when drive forward or reverse. I took the car to Porsche dealer and they mentioned it's the transfer case need to be replaced. The parts are on order and should be available in two weeks for the update.

 

I'm part of the transfer case club. Mine has issues at 47K. Getting replaced next month under CPO. Apparently, the newer ones are more stout. Between this, and aluminum cam bolts, a surprise for Porsche quality. Makes me think about what's next.

I still cannot believe trans fluid is changed at 100K. My excellent dealer was adamant to do any preventive, said was $900 to change if really wanted too.

 

Hmm... somewhere I made a longish post on the transfer cases. I think it might have been over on renntech - but I figured I'd also follow up here.

In one thread somewhere (?) a chap showed a photo of his repair bill for the new transfer case ("X-case" from now on) he received. He mentioned that Porsche had changed the design and that included a modified X-case vent that vented up higher.

On his repair order was the PN of the vent - 958-301-047-10. Available from Sunset Porsche for $28.71 (plus shipping.) I thought I'd drop by my FLD* and give them a shot at it, and see if I could glom any more info.

Turns out it was a good day to do that since they just finished replacing a X-case on a 958 /S - and had the old one on the shop floor waiting to get boxed up and returned to Porsche.

What I found out:

- The X-cases are still made by the same manufacturer. Indeed - the ones available are generally REBUILT ones done by that manufacturer. So - same basic design.

- The vent IS a change. On the existing X-Case the vent comes right out of the top of the large cylindrical part of the case (where the clutch lives) and is capped by one of the rather common fish-mouth sort of rubber caps that Porsche so loves (they are a sort of 1-way device - at least supposed to be for moisture. Maybe.) This cap just slips over a small hose sort of fitting that threads into the top of the case. The idea being that air can pass through the fish-mouth part of it

Took forever to find this:





The old transfer case was right there - so I got to look closely at it. As part of the kit - the fitting on top of the case is unscrewed and a new fitting screwed in that connects to a corrugated plastic tube (Porsche is SO fond of these..) The plastic tube is then run up the firewall into the engine compartment - with all sorts of neat fittings and clips and tie-off points. The idea being - move the input to the vent to a dry heated area.

Problem is - the clearance isn't there to do this replacement with the X-Case in the vehicle.

BUT - my thinking is - simply remove the rubber cap/seal - put some high-temperature teflon tubing over the end of the existing fitting and run that up into the engine compartment. Come up with some way of using the existing rubber-seal on the end of that tubing.

So - that's the plan.

I'll be doing this while changing the X-case fluid. The shop-lead mentioned that the fluid is spec'd as "Lifetime" fill - and I just pointed to the X-case sitting on the shop floor - that apparently had exceeded it's lifetime. He agreed that a change of fluid is probably a good idea.

Next challenge - which fluid?

There is 000-043-301-36OEM - which was "superseded" by 000-043-305-63OEM. Cost at the dealer was around $75. Cost from Sunset Porsche is $47. I gave the dealer a chance to make the sale - but the difference is simply too much, even figuring I'll have to pay shipping from Sunset. The first oil is also available from Pelican for less $$, but I think I'm going with the new oil.

Oh - one other change the shop lead mentioned they make to the new X-case - is a new slinger on the output spline shaft, apparently to toss water differently from how it's tossed now if the vehicle is driven in heavy rain or water.

They were told that the "fix" for the cases is to keep the fluid from getting contaminated - and that's the reason for these modifications.

I'll try to remember to take some photos.

* FLD = Friendly Local Dealership

 

So Don,

Do you think the replaced X-case my 2012 S received in January is this one you speaks of with the new venting system?

 

Oh - one other change the shop lead mentioned they make to the new X-case - is a new slinger on the output spline shaft, apparently to toss water differently from how it's tossed now if the vehicle is driven in heavy rain or water.


My knowledgeable tech said the reason X-Cases go south was a poor original design.

 

If it received the vent kit - it would be listed on the invoice - even if you weren't charged for it. The PN is: 958-301-047-10

 

The "design" is identical in the basics to every other electronically controlled transfer case. If you do a search on transfer cases - and look at other single-speed ones - they ALL use a multiplate clutch - a metal chain/belt - and a planetary gear. And many seem to fail due to stretch of the chain/belt (especially BMWs - which exhibit slightly different symptoms than the Cayenne does.) The stretched belt gives a lurching effect on acel and decel - and some slapping noises if it hits the inside of the case.

If it was overall a design not capable of the power being fed to it - I'd expect ALL Turbo ones to fail rather early in the vehicles life. That doesn't seem to be happening. In talking to the service advisers the other day - they said that they do a lot of the /S models for some reason. They couldn't recall having a turbo needing replacement. I'm sure some Turbos have failed, but not an inordinate percentage considering the increase in HP and torque going through the TC.

It seems that based on the "fix" Porsche came up with - they believe fluid contamination may be the issue. Contaminated fluid could alter the behavior of the multiplate clutch (and indeed - the recalls on the very early 958 TC was described as being caused by a poorly machined clutch assembly.)

Your mechanic is obviously right - a well designed case would never ever fail. Certainly the failures would indicate a bad design - but what part of it is badly designed - has yet to be determined. I haven't heard or been able to find any information on someone rebuilding the cases.

 

Being a new 2012 Cayenne S 62K miles owner outside of any warranty, I took the approach on this, and all of the other fluids, except X-mission, to change them out with new. Even with the new superseded fluid P/N at north of $50 bucks a quart, I believe this is money well spent. My fluid drained relatively "clear" as reported by the Tech at the local Indie dealer. I bought my optioned car ($85,005) for $32,500. No leaks anywhere, no aluminium Vario-cam bolts, brakes at mid-point, and everything works as it should. I guess we'll see in the long term. As an owner of many vehicles over my lifespan, and a Licensed Airframe & Powerplant mechanic by trade, I believe the Porsche service intervals on most items are too long. Preventive maintenance is cheap compared to the breakdown!

 

Thinking I've dodged a bullet on mine. Had the symptoms with the jerkiness and with just changing the oil in the xfer case it has gone away. I've driven it all week under various types of driving. I'll change it again this weekend or next to make sure the last bit of old oil is out. So this might be something that can be "fixed" upon the initial onset of the symptoms.

 

After replacing TC, and rear Diff, and reading how some have experienced multiple failure's. I inquired about the reprogramming of these replacement components . My SA sent me this document showing the work was performed on mine. Yet this was done as a preventative by the sounds of it under service Campaigns
, not necessarilly a requirement upon replacing unit(s). So assuming this has been done in the first place , it would appear unnecessary after replacing either TC, or RD.

 

Sybco - since that's listed as WC26 - it must have been described in a workshop campaign bulletin. Wonder how we might get a copy of that..

One thing that is called for in the factory service manual is resetting of the wear-indicator records in the all-wheel-drive module when the transfer case oil is replaced. I'd assume this also is done when the TC is replaced.