garrett376

Fuses are probably easiest: Right side of the dash, #2 slot 15A fuse is the PASM control unit power; if that's dead, nothing will be going on with the level control.

RAudi Driver

Before you go and put that car on a lift and hit the gas, check your driveshaft. I think Garrett has it correct in that it sure does sound like a driveshaft issue.

mikescayenne

we checked the driveshaft there is absolutely no movement or play in it at all. Also the sound seems to be coming from the front passenger side wheel. Also, both front wheels dont seem to spin as freely as the rear wheels do (when on a lift and just trying to spin the tires). I'm thinking its the wheel bearings even though the wheels have no play at all or make any other sound when turning left or right. This sound could be early symptom of wheel bearing issue.

RAudi Driver

Check for 12/ 6 o'clock wheel play for bearing check. I doubt it's your bearings but I've been wrong before. How many miles on the car?

mikescayenne

116k miles on the car, seems like right time for bearings to *begin* to fail.

RAudi Driver

125k on mine. No bearing failure yet.

mikescayenne

We found the noise it was not wheel bearings. Thank you so much to @garrett376 for telling me which fuse to pull for the air suspension, it totally turned off level control, we got it on the lift, and put it in drive. Right away it was very obvious where the sound was coming from, the front diff, where it connects to center driveshaft. I think thats the pinion bearing if im not mistaken making that sound? Does anyone have a DIY on replacing the pinion bearing? Do you have to drop the entire diff, or is there a way to do it with the diff still up and just removing the center driveshaft/transfer case/etc? Anyways here are the videos, sorry they aren't better i was focusing so much on the noise i didnt aim the camera that well, but you can hear it loud and clear (the 2nd video is much better), let me know what you guys think:

CAVU

Wow! That is perseverance!

This video may be of some use and a place to start
Someone on this forum recently dropped his front diff (aka front-axle final drive) and made the special tools to drop it safely. https://rennlist.com/forums/cayenne-...l-failure.html

I certainly would confirm the differential as the source with a mechanics stethoscope.

A rebuilt one from Porsche is about $1500 before S&H and after exchange, but these exist on three different frames Porsche, VW and Audi so the wrecking yards probably have a few of these available.

mikescayenne

haha, I watched that video as well, dropping the diff and opening it up is not for the faint of heart. Much easier to just replace the entire thing, labor cost of opening up the current one and servicing it would be the same as swapping for a used one. Most rebuild kits are like $300-$400, and the labor to drop it and open it up would be way more than just paying $900 for a used, low mileage one that can be swappped in. The issue with the ones in the VW and audis, is i have a Cayenne S with the 4.8L motor which has a different ratio (3.09) than the base cayenne's with the 3.6 that the vw and audi's shared with the cayenne so i have to find one from a cayenne S, even the cayenne turbo front diff has a different ratio as well and wont work in my car. Im hoping someone comments on the sound, and says it sounds like its just the pinion bearing and if thats an easy thing to replace. I cant find any DIY or posts on replacing the pinion bearing in a 958 cayenne though.

Finally, most 958.1's have high miles on them at the yards, and i dont want to risk getting one and it failing again so i want to find one with low miles (up to 60k miles at most). Anyways, will let you guys know what i decide to do. Going to start by flushing the fluid again and seeing how much metal is in it. If someone has any experience with 958.1 differentials, please comment!!

mikescayenne

ok ive been searching for the bearing/gear that the center shaft connect to the differential with, and i think i found it. Can someone confirm that this is indeed the bearing that the center shaft connects to the front differential with, or am i looking at this diagram incorrectly. Im thinking its either part 17 in the diagram, or if it's the part that number 21 connects to, i have a picture and part number of that below? Thanks.



This is the part i think it is....

Drive Axle Shaft

Part Number: 95834927240

CAVU

neither:
#17 is a rubber mounting
#1 is a drive shaft (cv axle assembly output)
95834927240 is also output.

Try a google search for 2013 front differential repair kit. seems to be quite a few on ebay. I have had my best luck with bearings made in the USA, Europe and Japan.


For your viewing pleasure. Me thinks this bloke has rebuilt a few of these:

CAVU

consider sending the sample out for analysis. Blackstone does gear oils also.

mikescayenne

i talked to a bunch of people today. all said most likely need a new front diff. i think im going to just cut my losses and not waste more money investigating it and just source a used one and replace it. Especially because its very common for them to fail on the v8 cayenne's, so im sure the end result of investigating is going to be that it needs to be replaced. Its just so strange the timing with the fluid change. it was probably going to happen anyways. Its a hard pill to swallow but going to just purchase one with the least miles i can find.

Can we fly that scottish bloke to chicago? LOL that video provided me some much needed laughter during all this.

My buddy and i were joking around saying lets just remove the front diff, weld off the transfer case and have a RWD cayenne lol, i told him if i lived in the south i would seriously consider that haha

CAVU

he and his shop are a hoot. calmly dropping f-bombs, has the empty case half in the vice at 4:20 and at 10:20 is finished with no video cuts, finding 100% of the parts on a bench covered in 6" of parts, knew where every shim was to go, soft touch with the hammer, being sure about the orientation of the axle tube, his buddy shooting the video wiping up the oil on the bench (he was reading my mind), etc. Too funny. My son rebuilds 240SX diffs and his f-bombs are not so calm, but he is 33 and time might soften him...maybe.

I agree, very odd for such a rapid self destruct of the diff. What oil did you put in the diff?

mikescayenne

Liqui Moly High performance gear oil 75w-90, part number is LM20012