Jeff96-993

I bought an RS tranny mount a few years ago from a fellow Rennlister, p/n 964.375.055.80. Came like new, still had the factory label on it with that part number on the label. However, when you look at the part, there are two p/n's molded into the rubber, the correct 964.375.055.80 in one location and and the stock mount p/n 964.375.055.02 on the opposite side.

First question: Once you remove the label how do you know what you have?

And the stock part I removed from my transmission has the EXACT same markings. If the old one wasn't dirty I wouldn't know which to reinstall.

Second question: What's the chances my car came from the factory with an RS tranny mount?

I've owned the vehicle for 13 of it's 15 years, and the previous owner (a doctor) had it serviced at the dealer. I have all the records on the car, so I know it wasn't swapped at the dealer.

I'll try to post pics shortly of the mounts, once I figure out how to get close enough to snap a pic that shows legible markings.

Also, I weighed the old and new mount, both are the same weight. 14 oz measured on a postal scale.

Thanks in advance for anyone who can shed light on this mystery.

Jeff96-993

Pic attached... best I could do. Leg closest to you has the RS p/n on it, leg opposite has the stock p/n.

This is the new one I bought. Old one has the exact same markings.

Bill Verburg

The only difference is the rubber bush used, Porsche marks the RS rubber bushes w/ a dot of paint, does either of yours have a paint spot?

mongrelcat

I bought a stock mount from Sunset and it came with the same multiple markings. The label on the bag is 964.375.055.02. It does not have a dot.

Jeff96-993

The label was affixed like the one in Bill's pic, wrapped around the outside. I don't recall a dot on it, but when I pulled the label and cleaned it up I might have erased the marking.

My old one has no dot.

Any other checks? They both weigh the same, so the rubber bush cannot be more dense.

I could try to rig up a load/deflection experiment to check if they have different stiffnesses. Based on the weights, I'm thinking that will come out the same too. Will post if I get a result of reasonable accuracy.

k9doog

After four years, someone have an explanation to this two part numbers in the RS Tranny mount?, just got mine after waiting for 4 week to come from Germany, and it has no dot and two parts numbers
964 375 055 80 and 964 375 055 02 on the rubber like the first pic.

vincer77

Maybe do a durameter test on them? If they are different rubber compounds, there should be a difference.

Cupcar

There really isn't an "RS" mount, the ".80" part number is a SuperCup or RSR racing part number.

If both mounts are in hand, one can comparatively test with a blunt instrument the hardness of the rubber - the ".80" is significantly harder.

Edit: The ".80" I find is a 993 RS G50 31/32/33 gearbox part in a 993, for 964 RS it was in racing parts catalog, so my mistake here.

The interesting thing here is that my G50/32 has a mount that looks different than the ".80" part pictured here, it is missing the top and bottom holes. Otherwise the same.

Jeff96-993

Since I started this thread, I might as well weigh in on how I solved the problem. I bought and installed a solid mount. I couldn't find a good way to reliably tell the difference between the original and the RS mount, so I just gave up on that front and went a different direction.

BTW, I enjoy the solid mount. A touch more cockpit noise, sometimes a rattle from the clutch, but that's all music to my ears.

Leander

delete

Cupcar

This topic intrigued me and I went off half cocked and provided a bunch of inaccurate information before. So, I went to my parts books and PET to look things up.

First of all there is an RS transmission mount for both the 964 RS G50/10 gearbox and 993 RS G50 31/32/33 gearboxes and the part number for that mount is 964.375.055.80

There is another part number for the 964 Cup and that is 964.375.055.70 and one of these is shown below that I bought years ago from Porsche.






All the above look identical to the standard Carrera 2 part 964.375.055.02 .

But there is another part number for the 964 3.8 RSR 964.375.055.77

And I am wondering if that .77 part number came installed in my G50/32 shown below which is a very different design without two of the holes?? According to PET the G50/32 was supposed to have the .80 but obviously mine does not.

k9doog

Cupcar do you know why the RS mount have the two parts number on it? 964.375.055.02 and 964.375.055.80, that is what confuse me, it only should have 964.375.055.80?, thanks.

Cupcar

Sorry not to be clear:

964.375.055.02 = normal Carrera C2
964.375.055.80 = 964 and 993 Carrera RS
964.375.055.70 = 964 Carrera Cup
964.375.055.77 = 964 RSR 3.8

k9doog

Cupcar thank you again, I think that I am the one that is not clear.
I purchase the RS mount part # 964.375.055.80, but the mount have stamped on it the two parts #, the RS one and the Normal Carrera C2, that is the reason why I am questioning the part that I receive from the dealer, it is the RS or the Normal Carrera C2?, I have no way to test the density of the rubber.
In your second picture you can see the two part # stamped on the rubber on opposite side of each other.

Cupcar

If you have the parts in hand and take a blunt instrument to the rubber you will be able to tell which of them has the harder rubber