Ghost Ryder

I'm about to change the TC and differential oil. What's the recommended oil for the differential?

Does the 958 have a limited slip diff or just a plain open differential?

kkturbo

This web site has a lot of detail on the TC. I cannot answer your question about the diff.

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

Ghost Ryder

Thanks, I checked out that thread. I think the consensus is to use porsche oil, or Revenol for the Transfer case.

But I can't find any info on the differential fluid. There was one entry on using any GL5 oil as it's an open diff. But I would like some confirmation before doing so.

deilenberger

I've read reports from several people who have used a standard GL5 synthetic oil with no ill effects in the diffs. It's what I'll be using when I get around to doing the job.

Ghost Ryder

Thanks for confirming. Autozone has Castro syntrax 75w90 LS for $2 a liter. I just bought 4. Hope that's enough.

CarGuyNVA

For the rear diff, I'm not sure if there's a different diff oil/lubricant for the PTV equipped vehicles versus the non-PTV ones, since the PTV cars have the electronic locking diff. ??

r553

For my 2015 CD I believe the differential oil from Porsche is 000 043 205 30, got it from Pelican Parts.


UPDATE: for the Cayenne Diesel Porsche has updated the part number for the differential fluid to 000 043 305 04.

Ghost Ryder

Anyone know how much oil is needed for each differential? Also what's the torque spec?

r553

I believe the Cayenne Diesel front differential requires about a liter and the rear differential requires about 1.5 liters. I plan to change both this weekend and will confirm. I've read the drain/fill plug torque spec is 27 ft/lbs.


UPDATE: today I changed the oil in front and rear differentials. The front took less than 1 liter, the rear a bit more than 1 liter. Bottom line 2 liters will do it with a bit left over. The oil didn't look too bad at 30K. I've sent them to Blackstone to get a base line.

Ghost Ryder

Thanks for the info. I'm going to do it soon. What gear oil will you be using?

r553

If you look at post #7 above I'm going with the latest Porsche oil 00 043 305 04. Its about $65 a bottle at the local Porsche dealer with PCA discount.

Be sure to check if your car has a locking differential as that would likely take a gear different oil. My Cayenne Diesel has open differentials and uses this fluid. Since I'm still on warranty I'm using the Porsche fluid.

r553

I learned today that an 8mm 3/8 drive stubby allen bit is needed to tighten the fill plugs on my 2015 CD differentials. To reach 27 ft/lbs you need a 3/8 torque wrench. My 1/4 inch torque wrench maxes out at 200 in/lbs ( 327 in/lbs is needed to get to 27 ft/lbs ). Doh.

UPDATE: I could not get the Williams 35608 3/8-Inch Drive 8 mm stubby bit so I got this from Tooltopia:




Front differential has a cross member forward of the fill plug limiting height of tool.



The rear differential also has a cross member running close to the fill plug.

r553

Here are the front and rear differential Blackstone oil reports from my 2015 CD at 30K miles. These are non-locking differentials.




Front Differential oil 2015 CD



Rear differential oil 2015 CD