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According to the PET, there's 950-332-551-02 and 950-332-551-03.
The 03 part superseded the 02 part around 1993, introduced for the Turbo 3.6. What I was told back when i bought my car was that the factory changed the coating on the discs in response to customer complaints about noise and juddering.
AFAIK, the friction surfaces are not carbon fiber.
The mechanic who rebuilt my diff for the previous owner (done at the local Porsche dealer off the books) told the PO that the entire diff was superseded with the Turbo 3.6 unit and charged him accordingly. I had to break the bad news to the PO that he got jobbed by this guy. It just goes to show that you can't trust a certain fraction of mechanics.
Last edited by Metal Guru; 03-15-2022 at 04:24 PM.
I don't know if Porsche made adjustments to the discs for noise or not. My 3.6T grinds and makes noises at low speeds and in reverse. I am due for a fluid change this year and the last change I did had the friction additive which made everything quiet for the first 2k miles then went back to making noise. The TSB was written for the 3.6T and I have the original documents going back to day one of my car. The Original owner went back 3 times complaining and then was told it was an inherent problem and although it was noisier than most he had to live with it or add the additive. I had a US spec cup car for a while which also has the 20/100 LSD it did make some noise as does mine but nothing in comparison. The unit works fine but just sounds bad but I am OK with it as is. I will se what the fluid change does.
I used this in my C2 which I had just rebuilt the LSD on but is a factory 40/40 vs the turbo's 20/100. The 40% unit never made noise. I believe it is all in the 100% lock up that causes the noise and the plates to lock at low speeds when in reverse.
Anthony, I'm not an expert. I think.... The LSD slips are very tricky to get correct. Fresh rebuilds make them chirp at tight turns or sometimes fully locked up. You almost have to make them slightly looser at rebuild. The turbos can't do donuts to loosen them up. I know if someone does multiple burnouts/donuts on a 964 and not 965 it will be too loose and bounce around or clunky at turns. I was not happy with my 40/60 rebuild as it was too tight. I prefer 20/80. My experience is from about 5 previous builds. One being a 3.6 turbo that spun out at 160 mph. The Diff was very clunky. I rebuilt it, but it was too tight where the turbos don't do burnouts to loosen them up.
On this next build I'm not screwing with it as I feel they are dangerous at 150 mph fully locked up. "Short wheel base cars"
Scott you can't adjust the LSD without swapping out different thickness plates. Doing donuts won't help I autocrosed mine and spun out many times and did nothing. My LSD is surprisingly still good at the mileage and still makes the same noises since new which is common to all these. I just rebuilt my 40% and no issues. I have a guard 40/60 in one track car and a 993 40/60 with GT3 plates in the other and IMO the best setup for these. Even at 160 mph on track. I have not tried 20/80 but have been so happy with the 40/60 I think I will stick with it.
I had switched to the Mobil LS 90 before - is that also an additive type? It was clunky and bindy with that in as well so just to compare with this vs that fluid and whether it is causing the LSD to work or not work etc.
... but I guess there are SO FEW 964 Turbo guys left out there that even consider jumping on Rennlist to discuss these cars,... that it doesn't really matter any more where {in which threads} the discussions live.
I had switched to the Mobil LS 90 before - is that also an additive type? It was clunky and bindy with that in as well so just to compare with this vs that fluid and whether it is causing the LSD to work or not work etc.
The LS stands for limited slip, so yes it has additive that allows the diff to perform properly.
I momentarily switched to Delvac. It was horrible. If you want to fell what it's like to not have your diff work at all, this is the stuff. I could have added slip agent but I thought I'd try LS 90 and I was happy with the result.
My diff makes some noise when cornering and makes weird sounds when I'm backing up but I know for a fact it's doing it's thing so I ignore the noise.
Did she break your spoiler, Wicks?
I spent a couple of hours last winter carefully polishing my spoiler, slat by slat. After all that work, the only way I'd allow a honey to lay on it was if she was naked.
prolly 85 lbs soaking wet,... I suspect spoiler held up fine,... but just in case, I would have spent the effort to gingerly set her down on it. That's the kinda guy I am,... always going the extra mile