North Shore 911

As much as I wished it would have, the software update did NOT fix my tranny's problematic shifting. I called Loeber Porsche last night to book an appointment to sort this out once and for all. Speaking to the SA on the phone, he seemed to be pretty sure that in the absence of the resolution from the software fix, that the transfer case and valve cover are likely the culprits (and he actually noted that they have been seeing a few other transfer case failure on the 2012's). So when I dropped off the car this afternoon, I went for a quick ride with one of the mechanics so he could hear and feel exactly what I have been describing as a slipping/missed gear change. Fortunately, the mechanic felt the exact same thing and told the SA when we got back that we need to replace the transfer case and valve cover . He also confirmed that it tends to be worse when warm, which has been my experience as well. I'll provide a full write up of the eventual fix after I get it back hopefully on Friday. And did I already extol the merits of CPO coverage...?

So I think I will finally get this sorted out, and hope to get it back by Friday. In the meantime, I've got a 2016 Cayenne base to beat up on my daily commute

mlct

Good luck. Mine is coming up on five weeks at the dealer. Fixes attempted so far are software, transfer case, and valve body. A control unit was considered but rejected. Now the word on Friday is that it is inside the transmission. Should find out on Monday how much this all cost since I was about a month out of warranty when I arranged to bring it in. I did notice it before then but didn't act quickly enough or it also may have gotten worse.

All involved feel this is an odd failure and naturally I am not very happy right now. Hopefully I will feel better once it is fixed and the bill is not "too big". Have purchased two new Caymans (S and GTS), this used Cayenne Turbo, and an 07 Boxster race car in the last five years so perhaps that will count.

North Shore 911

Mlct,

Bummer that those fixes haven't addressed the problem, I can only imagine your frustration after not having the car (nor a proper solution) for 5 weeks now

On my side, I picked up my Cayenne S yesterday evening after Loeber Porsche replaced the transfer case and installed the updated vent line. After driving the car 60 miles (including a BUNCH of accelerations from 1st-4th gear to make sure that the slipping/skipping gears is fully eliminated), I'm happy to confirm that this DID fix the problem

Now to address the nail in the passenger rear tire that I somehow managed to pick up in the last 24 hours ....

mlct

Glad you are good now. Hopefully things will clear up this week for me.

gator9_911

Had the same issues on my '16 with 15k miles. Thought it was the tranny...but was in fact the transfer case. Apparently this is a know issue. Water leaks into the case and over time causes the jerks and hesitation to occur. My dealer diagnosed it even before they had the car. In and out in two days. Car drives like new! Never knew how much is was affecting things as it degraded over time.

deilenberger

At the risk of bringing a semi-dead thread back to life (last post 01/17) - @gator9_911 - who was it who told you about water getting into the case? I assume the service department? Any details you can add? If that was the explanation for early failures like yours that's probably the reasoning behind the revised vent for the transfer-case (hopefully yours got the new vent kit.)

North Shore 911

Not to jump in front of Gator, but I got the detailed description from the SA when I picked up my PiG from the CPO work to replace the TC. He grabbed the mechanic that did the work, and the way he described it to me was that the vent line for the transfer case was originally at the bottom of the transfer case itself. Apparently the issue was that the lower location would occasionally allow for moisture to actually enter the transfer case and cause problems. My problems were always worse when the engine/tranny was warm, which the SA confirmed was a sure sign of this problem. In the new cases they are installing, they told me that the vent line is rerouted to the top of the case where moisture can't penetrate the case via the vent line.

I think I posted a pic of the work order from the P Dealer in the "Repair/Warranty" sticky thread that referred to the installation of an "Updated Vent Line" (post #315 on that sticky). I'm not sure if this is consistently being updated on other TC replacements, but the SA at Loeber Porsche in Chicago seemed to indicate that they've been installing this new vent line kit on all of the TC replacements that they've been doing ...

deilenberger

Unfortunately - your SA and mechanic were wrong. The vent has always been on the top of the case - sealed with one of those birds-mouth sort of rubber seals Porsche loves to use (like on the cowl and AC drain lines).

I posted a photo somewhere with the vent circled.

Found it:





Vent is circled.

The vent sticks straight up (sorry for the horribly dirty transfer case - but that was the best picture I could find that showed the vent location..)

What Porsche now is doing is to fit a kit to run the vent up higher into the vehicle. As I think I've explained - there is an air-scoop under the car, attached to the edge of the transfer case. It's purpose appears to be to cool the transfer case by blowing air across the front side of the chain gallery (the long arm sort of thing) and the clutch housing (the barrel part) as the vehicle is moving. Of course the vent would only be effective if the Cayenne is moving. If you were stuck in mud or something - no way it would help.

Anyway - the same scoop would be remarkably more effective at scooping up water if you go through water deep enough to reach it. The water would be directed up at the back of the case, and some of it would be tossed on the front driveshaft/CV-joint coming out of the transfer case. Since that shaft is moving if the car is moving - it in turn would toss the water up and over the barrel part of the case - and right over the vent.

So - Porsche moved the vent. They also add a "slinger" (water deflector) to the front output shaft (the one that's visible on the left side of the case in the photo) - intended to redirect the water from the spinning CV joint.

The reason I was curious - I think we're seeing two different kinds of problems:

1. Low mileage TC failures - are likely caused by water getting into the clutch pack and rusting the plates in the clutch, causing "snatching" as the clutch slips (slipping is part of normal operation.) That's what yours sounds like. And there have been other ones that exhibited the same sort of symptoms at low miles.

2. Higher mileage TC failures - up around 70,000-110,000 miles I think are a bit "softer" failing. It's not as noticeable - and mostly shows up under acceleration 2nd-3rd gear and 3rd-4th gear shifts. It's sort of a slippage instead of a smooth engagement. A flare in RPMs then it grips. This I think is due to bad transfer case oil. Despite Porsche claiming it's "lifetime" fill - just the fact that they thought they needed a special vent to cool the TC to me means they were afraid of heat damage.

People who have changed their oil on the higher mileage cases - have so far 100% reported an improvement in how the case behaves. In several cases people reported a "burned" smell to the oil, which to me indicates it's been heat damaged. I suggest that people consider making changing the TC oil at every-other oil change (about 20,000 mile intervals.) Use either the Porsche oil (about $70) or one of the equivalent ones that meet the Porsche specifications. Changing the oil is one of the simplest maintenance jobs you can do on a Cayenne. The fill and drain plugs are right out in the open, nothing obstructing them, easy to reach. You should be able to get under your Cayenne easily by either raising the suspension if you have air-suspension, or driving the front wheels up one 2 stacked 2"x10" boards (about 24" long). That should provide ample room even for the rotund.

Anyway - thanks for the feedback. By their actions - it's obvious to me that Porsche thinks at least some of the failures are moisture related. I wonder if they'll ever change the oil-change interval on the TC's from silly to something reasonable.



PS: Still would love hearing from Gator..

vichang4

I have a 2012 base that is having the same exact problems as North Shore 911. Definitely worse when the transmission warms up. Mine is also certified preowned so it is going to the dealer next week. Will keep everyone informed of the repairs.

deilenberger

North Shore - I wanted to make sure your replacement was included in the list I'm keeping at https://www.renntech.org/forums/topi...comment=287292

Some more info - such as mileage would be helpful. Yours is a 2012 CS?

North Shore 911

Hey Don,

Yep, mine is a 2012 Cayenne S with 53k on the clock when I took it in for the TC replacement, sorry if I missed that earlier in the thread. Thanks for tracking all of this, I have to believe that this growing database will HAVE to generate an official response and resolution from the good folks in Zuffenhausen

vichang4

Got my 2012 back from the shop today. Replaced transfer case and "Installed updated vent line". Had the TC in stock! All covered by CPO. Brian Harris Porsche in Baton Rouge did the work and they had it ready to go in less than 18 hours from drop off to pickup. 48,000 miles on the odo.

CanyonBlaster

What is the result? Do all shifts/gears operate smoothly now?
My 958 GTS has bad (slightly clunky) 3-4 & 4-3 shifts. I am considering same pursuit with dealer. My car is also under warranty.

Thx!

deilenberger

Suggested reading:

https://www.6speedonline.com/forums/...-replaced.html

https://rennlist.com/forums/cayenne-...l#post14154682

https://www.renntech.org/forums/topi...er-case-fluid/

Might I ask that you try changing the transfer-case fluid BEFORE having the TC replaced? Just as an experiment?

So far we've had 100% success "fixing" transfer cases that start to get rough by changing the fluid. If you go to Porsche - they will simply replace the entire case. That's a rather expensive way to change the fluid, but I guess if they're paying for it - what the heck..

It takes about 10 minutes to change it, and it's EASY to do. The threads above provide details, sources/types for the oil needed and even links to the oil pump tools that make the job easier.

deilenberger

BTW - My '11 CTT - never felt particularly rough to me - but it wasn't silky smooth. I just put this down to the nature of the beast. It also never showed much boost (which it turns out is apparently another symptom of a slipping transfer-case clutch.)

First real long high-speed drive tonight of it since I changed the fluid. As much as it changed the around-town feel of it - the change on the highway is amazing. It is SO smooth now. And boost starts up as soon as I start putting my foot into it, and unlike before - the boost holds as long as I keep my foot into it.

It never felt awful before. It feels WONDERFUL now. I'll be doing a second change in another 500 miles or so - just to make sure I got ALL the old burned fluid out. And my suggestion to everyone with a gasoline powered 958 - make this part of the regular maintenance schedule. I plan on doing it every other oil change. It will add 5 minutes to an oil change. Well worth doing.