Last weekend my transmission was out of the car for clutch replacement, and even though the rear trans mounts were not broken I decided it was a good time to replace them with the cheaper and presumably longer-lasting 911 "sports" mounts. They were really cheap, so what the heck.

Can anyone share their experiences as far as noise and vibration go before/after such a swap? I'm experiencing vibration between 2500 and 3500 RPM, and way more transmission noise entering the cabin. There was never any vibration and a lot less noise with the old mounts.

Just wondering how much of an effect is to be expected with those stiffer mounts.

I installed the sport mounts. I didn't notice any extra vibrations or noise.

Installed semi-solid delrin mounts. Compared to cars with 911 sport mounts or stock rubber ones, my car sounds like a logging mill in all gears.

The harder the compound in whatever mount you use, the more noise and vibration will be transferred from the engine/trans to the body, which acts as a huge amplifier when you're in the cab without a lot of sound deadening.

I didn't notice added noise, either, but noise is always there from something...
Could it be that the old mounts just isolated more- for better or worse- because threy were old?

The old mounts were the original mounts the car came with, but only 28,000 original miles on them. There was no indication (including visual inspection after removing them) that they were broken.

What is the condition/age of the front engine mounts? Could firming up the rear tranny mounts amplify problems with poor front mounts?

That's a good idea, I'll look at that when the car is in Germany. Then I'll finally have a hoist and tools available.

Get the WEVO mounts...they are sweet. They also don't require modifications to the holes to get them to fit correctly. We put them on JP's race car and the shifting really firmed up. They are lighter also.

-Britain

they are much more expensive too ...

key word here is "race car". i wouldn't recommend anything solid (and yes, i consider the wevo mounts solid) for a mostly street driven car ...
Andy

Yup - we're talking all-original '76 2.0 chock-full of emissions goodies. Not a racecar by any stretch of the imaginations. I want maximum comfort and minimum noise/vibration.

If the mounts are not the issue, which I will find out when I put on a replacement set of original-style mounts (dang, those are expensive) the only other culprit could be something having to do with the clutch/flywheel. This would be the least desirable outcome

just something to check-- maybe installing the somewhat thinner 911 mounts you moved up the rear end of the tranny enough to have exhaust hit some part of the car/heat shield?

Good idea, I'll check that was well. Although if the exhaust touched the body I'd think it would be more obvious and louder than what I am hearing. Right now it sounds a bit like like the transmission is running without any oil in it

They didn't seem to cause anymore vibration in my car. I did feel more vibration in the shifter but mine is solid metal so it's gonna transfer pretty good.

But yeah I guess they are a tad more expensive.

I definitely noticed a change on my car especially at idle. More vibration into the chassis (makes my headlights vibrate sometimes, never used to do that) and more noise in general. So I would say YES they can make a difference.

Sawmill noises, made my headlights shake, more vibration, amplified the noises? Crap sounds like being in these cars would turn the girls on to a night of hot and nasty sex.

:beer1:In a motel with screaming orgasms.