So I installed the RRM semi-solid engine mounts (front and rear) and have noticed that I have a pretty good vibration during idle (transmission in gear) and in reverse. When I'm driving I don't notice any issues once my RPM is above 650/700.

I've cleaned out the throttle body which increased my idle RPM slightly, but it's still shuddering pretty good in the gears I mentioned. Not all the time, but after the car warms up.

I've flushed the system with new atf+4, didn't see a lot of metal shavings on the plug at all (just a bit of metal mud, more of a film than significant buildup). Then again, I just changed the fluid about 25k miles ago.

My stock mounts were busted. Replacing them has definitely kept my CAI and strut bar from making any noise (it was kicking so badly that my strut bar was hitting my intake manifold). And I probably never noticed the additional tranny vibration, but now that I've fixed the other issues this is the one that's raising it's head.


My question is this: Could I be looking at a bad transmission mount? OR, is this just something I'm noticing with more rigid motor mounts and I shouldn't be concerned? If it's the latter, should I just increase my idle RPM to compensate? I've read about doing so via evoscan (i do have a tactrix and ecuflash), but didn't want to mess with anything until I got some educated feedback...

Thanks!

 

No that sounds pretty normal. The stock mounts compromise longevity for the ability to dampen vibration. Your replacement mounts are much stiffer and will probably last forever, but will transmit lots of vibration. That's just the trade off.

 

+1
If it's not shaking real bad then it's prob. just the new stiffer mounts.
If you've ever used solid mounts then you'd think your car was gonna shake apart.

 

alright, gotchya. Do you think a stiffer tranny mount, and/or stiffer side engine mounts would make any difference, or just increase the noise?

 

I've got the RRM mounts in my ralliart which is also auto. It should vibrate quite a bit more in drive/reverse but should be fairly fine when in neutral. Its just the trade off of having stiffer mounts. With the RRM mounts in my ralliart the motor barely moves at all under throttle.

 

alright, cool. Just wanted to double-check that my tranny wasn't having issues that I didn't notice before the solid mounts.

Thanks for the input!

I've been trying to convince my girlfriend that I can put it in neutral at stoplights/traffic to stop it from feeling like a vibrating bed, but she doesn't believe me!

I'm probably going to do the tranny mount and one or both side engine mounts, just to cover all the bases anyway. Since my rear motor mount was completely split, I'm thinking the other mounts took a beating.

 

I just got rid of my OBX exhaust, and guess what, most of the shuddering is done. I think I had a flexpipe that crapped the bed, and that's what was doing it. It's still a decent amount of vibration in the cabin, but not nearly as bad. I'm still going to replace the stock side mounts, but not going to worry about the tranny mount for now.

 

What did you swap the OBX Exhaust with?

 

Generic $90 header and downpipe off of ebay, it's actually a better fit as far as how the pipes are bent on the outside. Smoother idle, less vibration. The guys that make em are out of cali. Better quality stainless than OBX, didn't turn a complete rainbow in 3 days