techman1

Yep, overlooked that information, seems def in the gearbox.

Shade tree mechanic thought, might be thinking wrong:
Remove transmission. Connect a runout gauge to measure input shaft.
With it in gear, turn the drive on transaxle to verify input shaft is true.

or did I miss this had been checked?

Peteinjp

good move- please post up the resolution. I'm sure Colin will get it sorted out!

Pete

cobalt

The second I heard microns I would have pulled my parts. Do they have a temperature and humidity controlled inspection room with gages that are calibrated regularly that can measure such tolerances? I highly doubt it. 2 or 20 microns to claim that accuracy with standard measuring tools is ludicrous. Sounds like a lot of BS to me and I would move on. If you have Colin offering to help I would be all over it.

nk993

Problem solved. Big thank you to Colin and @NineMeister . They solved in roughly a week what took others 6 months to not solve. I've been following his threads on here since the early 2000s before I could even drive! So very happy I was finally able to actually buy a 993 and work with them.

The issue is with the gearbox mount. The new stock mount supplied was rock hard, harder than RS. Its the new part that superseded the old 964 375 055 02 and its part number is 964 375 055 81. This one had both 964 375 055 81 and 964 375 055 82 printed on it, and there is no explanation for why. It had pretty much 0 give in it, which was transferring all the vibrations into the car. Replacing it with an old used 964 375 055 02 one fixed the issue.

Watson

Amazing found! Glad that your issue is solved! I suppose there is no way to find out the rubber is too hard unless you assemble it into the body and check the engine / gearbox displacement?

ed devinney

Very interesting. I put RS engine mounts and a new 96437505581 mount in my 993 in the Spring of 2019, and had a huge NVH problem until I replaced the RS engine mounts with stock. Next time I have the car on the lift I'll have to see if it's got both part numbers stamped on it.

IainM

I'm having the same issue and am building a list almost as long as yours. I looked at my invoice for refresh last year and sure enough I got the 81 part.
Where did you get the old -02 part from?

Thanks for following up and posting the resolution. This will help a lot of people I suspect.

IainM

OK, new information.
When I look closely at photos of my old tranny mount, it has part number 964 375 055 80, which is available from various places at the nosebleed price of almost $400.
Jason confirms that -81/82 is the RS 60 shore hardness, does anyone know if the -80 is the original 40 shore rubber?

TDW993

I was under the impression that the RS has a shore harness or 85 and stock is a harness of 65? Can anyone confirm as I have just ordered one from a supplier and it is supposed to be OEM at 65 which is what I thought stock was.in the other thread it says 40 so I am now confused.

911PERVY

Dont know who Jason is but part ending 80 is the RS version

Standard ends 02 and now 81

nk993

80 is RS, 02 is stock, and 81/82 is the replacement for 02.

based on Colin’s measurements of my 81/82, it’s way way way harder than even the 80 RS. He even recommended the 80 as a softer solution than the 81/82, which was closer to the cup car ones. Someone at Porsche ****ed up

TDW993

That makes some sense now. The 80 is the RS as per Bill Verberg’s photo on another thread, the 02 is/was the standard original unit. The discrepancy is the 81/82 which is the replacement for the 02 which was superseded some time ago. I guess the question is how hard is the 81/82 vs RS version?

IainM

I'm not buying it.
I had a -80 in mine that I replaced with a -81.
The -81 was much harder than what it replaced and now I have the same problem with noise/vibration as everyone else.

IainM

linking to parallel thread.https://rennlist.com/forums/993-foru...bration-3.html

911PERVY

Not buying it?

Sounds like you have had the exact same experience as Nik