f266

I have a 955 Turbo S with 131k miles. When I put it into drive or reverse and release the brake petal, the car doesn't move under it's own power. When I start it after it sits for a while, the car shakes unusually in all directions. Putting it into gear is really rough. If I shift it into first gear, or give it some gas, the car "rips" into drive, with a thud sound coming from around the front axle and driveshaft. Then after the car is moving, I can put it into reverse or drive and it moves as normal.
There is a loud constant/inconsistent clicking right under the gear selector. I read that this is related to the brake system, so I tested it and it clicks when I press down the brake petal. But the issue is that it is clicking randomly, while pressing down on the brake petal. I haven't noticed this clicking noise before.
There are no warnings on the dash, and the electronic drive select is working as normal. Cycling through the diff locks seems to work as normal. Could this issue be related to the bake system, or is my transmission or clutch shot? This issue occurred the day after I towed my boat. Driving the day after towing, right before the issue occurred, I noticed that the car was shifting rough.
The driveshaft support looks and feels intact:

The underbody is squeaky clean, with no leaks that I could see. Any more questions, feel free to ask!
Thanks.

deilenberger

This will require putting it up on a lift to determine where the failure is.

f266

Started the car up this morning, and there was no unusual shaking. When I put it into gear, front or back, the car moved as expected.
When I put it into park, the car kept moving forward a bit until it hit a hard stop. Then when I put it into reverse, the car shook front-to-back, engaging roughly but it moved.

Morganmobile

Check your transmission oil. Mine dumped all of it out through a whole in the transmission oil cooler and had similar symptoms.

f266

Thanks for the advice. Reading Brainz posts at https://rennlist.com/forums/cayenne-...l#post12898763 and his car's symptoms sure sounds like what I am experiencing.

Brainz

The lack of drive and then lurch problem sounds similar to a very low fluid condition, but your original post doesn't mention any of the usual causes of low fluid: 1) changed the trans fluid and filter (and didn't get enough back in) or 2) have an ATF leak at the cooler or front converter seal.
Low fluid, in my experience, isn't very noisy except for the "pop the clutch bang" that may happen if you rev the engine in hopes of getting drive to happen - - that can shock load the drive train and make noise when the clutches engage.

I'm a little worried about the grinding/clicking noises you hear and that this happened after towing. How heavy was your trailer and how much towing did you do? That makes me wonder about the trans clutches (burnt/worn) , the transfer case (stretched chain), and even the drive shaft (damaged splines). Most of these issues are pretty rare in the forum, but there have been rare reports of such.

I'd do the following:
1) Check for obvious fluid leaks
2) Check for play in the driveshafts
3) Does activating 4wd center diff lock change the symptoms?
4) Open the fill port on the trans with the engine running? Does any fluid come out? A properly filled trans will dribble a bit. If not, put more fluid in there (with the engine running) and see how much it takes.
5) Consider draining the trans and dropping the trans pan. Look for friction material or debris in the fluid. Replace the filter and refill - - it should take ~7 quarts, maybe more if you let it drain overnight.
6) Change/check the fluid in the transfer case. Any debris?

One other thing: Is your engine building boost under load? The CTT[S] will drive like crap if you blow a boost hose - - and it will feel like your trans is the problem. Check the boost hoses into and out of the intercoolers and into the Y pipe on the manifold. Your symptoms don't sound like this, but wanted to mention it.

f266

Thank you so much Brainz for the reply and your expertise.
The car is new to me, and I've driven it less than 1k miles, so I don't know when the trans fluid was last changed. Are there any resources or diagrams online so that I can find where the cooler and converter seal is located? I tried googling the cooler location, with no luck. With that being said, there are and were no leaks on my garage floor since I got the car. The tans oil pan isn't leaking.

There is no "grinding" specific noise. The clicking sounds very much like the gearshift solenoid that is associated with the brake system.
My trailer is 2500 lb and I hauled ~80 miles that day, 40 miles each way.

It's building boost as normal while I was towing. Plenty of torque.

I'll run through your 1-6 check list. But I don't have a computer to check the oil temp. Does a Durametric or ICarScan read the temp?

Brainz

I'm not an expert, just an enthusiast schooled in the [many] hard knocks of Cayenne ownership.

The ATF cooler is a rectangular, ribbed aluminum unit that sits at the very front bottom edge of the engine next to the oil filter canister. There are some hoses/pipes that connect to the cooler that some have had leaks with -- I do not have experience fixing that (knock wood). The front converter seal is buried inside the bell housing to the transmission. If it's leaking you'll see fresh ATF drops on the bottom of the bell housing. Replacing the converter seal is usually best left to a professional -- it's usually ~$1000-1500 to fix.

A 2500lb trailer load is nothing for these cars -- other than the noise from the hitch, you'd likely never know you were towing anything. And it's good that you're not hearing grinding noises.

Since your CTTS is new to you, based on your symptoms, it's probably just low on ATF. You should probably change all the driveline fluids for good measure since their condition is unknown. Note that many (myself included) have messed up the o-ring on the transmission filter while replacing it. It needs some lube and should be pushed square into the receiving bore to seat correctly. It's easy to get it crooked and have the o-ring not seat right. When this happens, the trans won't suck up enough fluid and you'll get the lack of drive problem. If it's just a little low on fluid, you'll notice it as a temporary lack of reverse first thing in the morning. The lower the fluid gets, the more you're likely to start losing drive too.

While not absolutely necessary just to change the fluids, Durametric and/or ICarScan are highly useful for Cayenne ownership. In your case, I'd want to use them to reset the transmission adaptations, which can sometimes markedly improved shifting behavior. IMO, the scanners are not critical for reading the temp of the trans when filling -- if you work fast (and use a pressure sprayer/pump) to fill the transmission, you can usually fill the transmission before it gets too warm. It usually takes about 10-15 minutes at idle for the trans to get over 40 C (which feels warm, not hot to the touch). If you try to fill using a typical auto parts store oil pump that screws onto the top of the bottle, you'll take more time than that (and probably break the pump and/or get really tired before you're done).

Good luck and let us know what you find.

95_993

Yes, Durametric and iCarscan both read fluid temp.

f266

I got the iCarScan and the EZdiag app. I don't see anywhere where I can read the trans temp. Where would that function he located?

VulcanGrey

That's the engine oil cooler. The transmission cooler is a thin rectangular in front of the engine coolant rad, near the top. It is visible through the front of the car openings. If it is leaking, the transmission cooler and radiator will be coated with oil and Crap.

Brainz

You're right! I got them confused. Thanks for the correction.

f266

I finally got around to checking the fluid level. I got the temp to 40 degrees, then opened the fill port and a bit initially came out (pictured). But then it was one drop ever 4 seconds and then slower and slower.

+ some more covering my glove. Please excuse the nasty drain pan.

The fluid doesn't look bad, so should I buy some to top it off or do a full change and differential while I'm at it? Will the Toyota Type 4 work ok, like recommended by DIY Dan?

kadn33

The Repair Manual I've got says the following:

And the AISN manual states the follwing:

Note that the only difference is that the car repair manual asks to leave the lever in N and the AISIN manual states P instead. Other than that and from your findings I would say the level is fine but in any case a fluid change will always be the safe way to go at 131k miles IMHO.

95_993

Toyota Type IV is the way to go. Same stuff, 1/8 the price.

Sorry I missed previous reply on trans temp. I forget the exact menu without firing up app, but essentially it's the menu under FULL System scan that lets monitor real time values.

Since the trans appears full, then it's likely not a leak. You could investigate further by picking up a few quarts of type IV fluid, removing the pan, inspecting or replacing filter, refill. If someone replaces the filter recently, it is possible the filter/o-ring is not seated properly.