I'm addicted to LSD!
#16
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Mine doesnt make any noise and it works as far as I can tell. 90 model, stock optional lsd. 114k miles. It could have been renewed at some point, but I have the complete records and I havent seen anything about it.
#17
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Originally Posted by Oddjob
Thats interesting.
I've had 3 cars with factory installed ZF LSD transmissions. None made any different noise than open diffs, mileage on those cars ranged from 21k to 97k.
I just rebuilt a 944S2 transmission and swapped in an LSD from a spare 135k mile 944T trans - I disassembled the LSD, the friction discs were fine, and the slip torque was still within the factory spec range.
I believe that the design of the 964 LSDs is the same as the 944 ZF 40% LSDs.
I've had 3 cars with factory installed ZF LSD transmissions. None made any different noise than open diffs, mileage on those cars ranged from 21k to 97k.
I just rebuilt a 944S2 transmission and swapped in an LSD from a spare 135k mile 944T trans - I disassembled the LSD, the friction discs were fine, and the slip torque was still within the factory spec range.
I believe that the design of the 964 LSDs is the same as the 944 ZF 40% LSDs.
I don't know about the difs being the same in principal, but the "standard" 964RS LSD is a 20-100% one.
#18
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Originally Posted by SimonExtreme
I don't know about the difs being the same in principal, but the "standard" 964RS LSD is a 20-100% one.
The 20/100% LSDs in G50 -10/52 transmissions use all 950 based part numbers, so although the design is the same, almost all none of the parts are interchangeable with regular 964 C2 LSDs.
#20
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Originally Posted by NinetyOneC2
is it normal for the LSD in this car to be a bit graunchy in very tight low-speed turns.
Originally Posted by Oddjob
I believe that the design of the 964 LSDs is the same as the 944 ZF 40% LSDs.
![](https://members.rennlist.com/jandreas/964-LSD-Installed.jpg)
Originally Posted by Oddjob
How many miles are on these cars that have completely worn out LSDs
#21
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Originally Posted by JasonAndreas
If your 964 has either of the two standard (40% or 20/100%) clutch disc based limited slip differentials you shouldn't be hearing any noise from them. If you are hearing a noise then most likely you have the wrong type of transmission lube.
It's not often I have the opportunity to disagree with you and be on strong ground but having driven or been in numerous 964RS's, I have never come across one that doesn't make noise at low speed. This is even reported in magazines at the time the car came out so that would mean that Porsche was using the wrong lube. The level of the noise can change with the lube you use and maybe, on a standard C2, the soundproofing means you cannot hear a properly lubed LSD but I can assure you that with the lack of soundproofing on an RS, you certainly can. You should hear how loud it is in a stripped out clubsport or cuppie!
You also hear the same diff noises, from new, on GT3's. This has recently been illustrated by one of the UK GT3 fraternity changing their LSD to a new Plasma Nitrided Motorsport one and one of the things he reports is that the LSD is now totally quiet. Others on the forum he reports that on wonder whether that is a benefit, because they like the noise!
#22
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Originally Posted by SimonExtreme
This is even reported in magazines at the time the car came out so that would mean that Porsche was using the wrong lube.
![thumbup](https://rennlist.com/forums/graemlins/thumbup.gif)
Originally Posted by SimonExtreme
The level of the noise can change with the lube you use and maybe, on a standard C2, the soundproofing means you cannot hear a properly lubed LSD but I can assure you that with the lack of soundproofing on an RS, you certainly can. You should hear how loud it is in a stripped out clubsport or cuppie!
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Originally Posted by SimonExtreme
You also hear the same diff noises, from new, on GT3's. This has recently been illustrated by one of the UK GT3 fraternity changing their LSD to a new Plasma Nitrided Motorsport one and one of the things he reports is that the LSD is now totally quiet. Others on the forum he reports that on wonder whether that is a benefit, because they like the noise!
![](https://members.rennlist.com/jandreas/Mobil1-SHC-75W-90.jpg)
#23
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Originally Posted by JasonAndreas
Yes and there might be a TSB covering this with the suggestion to use an LSD additive to quiet the noise?
(I don't have the TBSs that were originally published for the Turbos) Porsche eventually changed the inner disc friction material from Gylon (carbon) to Valeo (graphite) possibly for this reason.
![thumbup](https://rennlist.com/forums/graemlins/thumbup.gif)
The level of sound-proofing in an RS-A is equivalent to that found in the RS Basic and if your RS is stock then my RS-A has even less.
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#24
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Originally Posted by SimonExtreme
I don't understand what is going on here because I have been doing some checking.As I have said, every 64RS I have been in has sounded the same and 996 GT3 owners report that they heard their LSD's from new and still do, even the only one I can find that is still serviced by an OPC!
Originally Posted by SimonExtreme
Since then, the car has been looked after by 2 highly respected aircooled RS specialists. I cannot find on a single invoice a charge for LSD additive. Are all these specialists getting it wrong?
Originally Posted by SimonExtreme
I know this is OT, but out of curiosity, what have you taken out that I have?
#26
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I think all the lube change does is quiet the diff. There is no difference in the diff's abilities to do it's job. The noise is normal on RS models with the standard lube. I thought there were specific reasons (can't remember what) for not using friction moddifiers in our diff's?
It does seem strange that almost all the RS owners I know and cars i have driven have all had diff noise.
It does seem strange that almost all the RS owners I know and cars i have driven have all had diff noise.
#27
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I was looking at my records again, to see what has been used on the car and the most interesting thing is that the gearbox oil got changed by 2 different specialists who have recorded the work being done but have forgotten to charge for the gearbox oil! One of them was when the LSD was rebuilt so I know that they didn't forget to do it! The PO was obviously a lucky man as that sort of thing never happens to me. However, if he saved £50 in the 4 years of ownership, good luck to him, particularly as I have benefitted from the £14,000 he spend rebuilding the mechanical side of the car
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#28
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Originally Posted by pncarrerars
I am using Mobilube SHC in my 964 RS & the diff is just as noisy as ever.
Originally Posted by Laurence Gibbs
I thought there were specific reasons (can't remember what) for not using friction moddifiers in our diff's?