Kenrevo

I have a front end noise; that started about a month ago. It sounds like a wheel bearing but the sound isn't constant. I always get the noise on partial throttle or on lift off. It starts around 20mph and goes away with the road noise around 60mph. It also goes away if I put the transmission in neutral. I thought it was the front differential and drained the oil it was dark and old but no metal in it. I'm now thinking it might be something else or is early enough to show signs of wear. I am due for new tires and the fronts are worn about a 1/16th more then the rears.

Anyone have any thoughts?

It is a 2014 Cayenne Turbo S with 78k.

AnAlbumCover

Sounds like the problem is in the transmission or between the diff's and transmission..

Kenrevo

I did a transmission flush and filter change over the weekend and it looked like normal old fluid. Just a minimal amount of metal particles on the magnets in the bottom of the tray. The transfer case was recently replaced by a pervious owner; I don't know the exact time but my guess is later 2019 or early 2020 based on the controller's information.

orangedawg

I may have a similar issue. No noise when power applied, but once I let off, I hear a hum and get a slight vibration in the steering wheel. Any idea what this might be?

AnAlbumCover

If you guys are putting the trans in neutral, it stops spinning (more or less). The only thing left spinning are wheels (bearings), the gears in the diff, the two driveshafts and maybe some stuff in the transfer case? (I'm not sure what the TC does when the car is in neutral, I would guess all the clutches disengage...)

I would inspect all the bushings, carriers and joints between the TC and wheels.

orangedawg

Thank you! Next time I am on highway I will put it into neutral and see if noise persists.

orangedawg

Okay, I put my CS into neutral and the "hum" and steering wheel vibration (it vibrates slightly when making the noise, not all the time, just when making the noise) went away.

Kenrevo

Just to update this thread uncase someone has similar issues. It was the pinion bearings in the front diff/ carrier, I replaced it and the sound went completely away.

mmgilbert

I'm also having a similar issue. How hard was the replacement? Is the pinion bearing the same as the front diff bearing?

Kenrevo

The job wasn't bad but I have done it in a couple Touaregs before. I did use tools not everyone has: 2 jacks, 5 jack stands, subframe alignment pins (Special tool T10300, to avoid having to get an alignment), and a 4ft breaker bar (for the additional 180 degs on the subframe bolts). You have to support the engine; Porsche says to support it from above with an engine lift. It can be hard if the car is 18" in the air and you have to trust a hydraulic jack to hold; I put a jack stand under the crossmember. I had to put the bolts back in (with spacers) and remove the jack stand as I needed the space where the stand was to remove the carrier. The hardest part was positioning the carrier to come out the bottom of the subframe; the PDCC lines only allow the subframe to drop so much (another 2 inches would have been nice). In the Touaregs I could drop the subframe enough to take the carrier out between the subframe and bottom of the car, much easier.

The front diff/ carrier has four bearings two on the pinion shaft and one on either side of the differential cage. On my diff the pinion shaft was making noise.

mmgilbert

Thanks for the writeup. Might be a lofty task for me. Going to take it to my local shop and see how much they would charge.

mmgilbert

Could you send me a link to the bearings that you purchased? Most of the ones I'm finding online are for the previous generation.

https://racingdiffs.com/products/aud...ial-repair-kit

Kenrevo

I haven't rebuilt my diff yet. When I do I'll post the part numbers I use. It wouldn't be until the fall, the rest of my summer is crazy.

orangedawg

I had a similar noise as I noted above: sounded fine when accelerating, but when let off the gas it would hum or a similar sound. I just took into the dealer this past week, they replaced transfer case under extended warranty. Sound went away, so maybe that is the issue as others have noted.

BTW, if you are still under the extended warranty, see if they will replace the TC. Also, I took into one dealer a couple of years ago and they said TC was fine and did not replace. This week I was coming to end of warranty (2014 CS), so I took it to another dealer. Dealer diagnosed it was TC and replaced for free. So, if they reuse to replace, take it to another dealer.

mmgilbert

Update on my noise. Indy shop found metal shavings in the diff fluid, so that was definitely the issue. Called a dozen shops to get quotes on repairs/replacements. Only 1 shop would do a rebuild, but the waitlist was way too long. Ended up getting it replaced for about $2.5k.