Urethane trans mounts - increased cabin noise?

[CraigBurton]

Hi All,

I just adjusted the valves on my 325i, and put on urethane transmission mount bushings. At first I though I had adjusted the valves poorly, as when I reved the engine the noise in the cabin was much louder and of a different sound.

I don't think it was the valve adjustment as only one really needed to be adjusted (worn eccentric, that I'll replace in a week or two.) but the amount of noise being transmitted through the drive train through the urethane bushings is crazy.

I have no carpet, or sound deadning in the car (its pretty loud already) but the urethane (engine bushings went in in last summer) trans mounts seem to have increased the noise a lot.

Has anyone else experienced this?

Craig,

[KenC]

Urethane tranny mounts will increase cabin noise a lot.

[Mike]

What brand are you running, and what car?

[CraigBurton]

Hi,

It's an 89 325i, the mounts are from Ireland Eng. The old ones were like marshmallows. Mmmmmm, marshmallows.

Craig,

[andym3]

I have used IE tranny mounts on two cars. Much louder but tolerable, especially since cars see track duty. I also have all urethane bushings, mounts and IE exhaust so it is all noisier.

[p0cket penguins]

Yes

[CraigBurton]

Ok, I'll take it just as a result of "race car'ing" I've never driven in a track ready e30 (or any race car) so I wasn't expecting much of a difference. I didn't notice a big change with the engine mounts, so I was a little supprised.

[Axxe]

Trans mounts make it a lot rougher than the motor mounts. I had hockey puck engine mounts (basically solid) while my new parts were coming in, there was barely any noticeable vibration. Urethane trans mounts make it a bit louder, but it's a good compromise for all the drive train slop removed.

[Lance Racing]

I'll throw this out. My crew chief for our E30 PRO-3 race car runs stock tranny mounts on the car. Everything else (engine mounts, etc.) are solid. He does not feel the solid mounts on the tranny are worth damaging the fragile tabs that tranny mounts attach too. If you have an off, and the engine/tranny mass moves, we've seen those tabs on the tranny break. Then you are junking a good tranny because the tabs broke.

I happened to have an off and impacted a tire wall sideways, and one of the stock tranny mounts sheared in half from the impact. We think we saved a tranny by having the tranny mount be the weak link.

[kishg]

I'll throw this out. My crew chief for our E30 PRO-3 race car runs stock tranny mounts on the car. Everything else (engine mounts, etc.) are solid. He does not feel the solid mounts on the tranny are worth damaging the fragile tabs that tranny mounts attach too. If you have an off, and the engine/tranny mass moves, we've seen those tabs on the tranny break. Then you are junking a good tranny because the tabs broke.

I happened to have an off and impacted a tire wall sideways, and one of the stock tranny mounts sheared in half from the impact. We think we saved a tranny by having the tranny mount be the weak link.

good point.

[Knockenwelle]

I am of the same school of thought on this one. I'm using all solid mounts, including the trans. But I've also got about 3/8" of reinforced rubber pad between the trans and mounts to soak up any chassis flex or driveline shock that might otherwise break trans ears. So far, so good, and the total lack of compliance is nice, too.

[themitchster359]

good thread...i don't think i'll be swaping my stockers then

[zaust]

I did have the same polly's on my box. But they did not last long. Have gone for mjg ally one's now and yes I have the same noise but they seem very storng.

[etxxz]

i could not put the IE tranny mounts in my s52 e30 becuse it would vibrate too much. Urethane motor mounts and stock tranny mounts is where i sit and i can barely tell the difference in noise. IE tranny mounts was a HUUUUGE noise maker.

[Kingb]

Ok so now I read this after buying AGK 75D motor and tranny mounts. haven't put the motor back in but now I know what to expect.