Has anyone installed a Polyurethane transmission mount in their car and experienced a bad driveline vibration? I broke the factory mount a while back and installed a poly one and ever since then it's shook the car so bad over 55 mph that it feels like the cars flying to pieces. My concern is something isn't aligned right, I installed the same mount in my third gen a few years ago and it was as smooth as stock so why is my 98 shaking so bad? I replaced the poly mount with a factory rubber one last night and the car rides smooth again. I know rubber takes the vibrating out but good Lord it shook so bad I thought the thing was going to fall apart. I just wanted to see if anyone else experienced this on their 4L60 E. Thanks

 

mine shakes a little to. but i was told it is cause it is a stiffer mount and the motor virbations are what you are feeling. it doesnt bother me to much though.

 

Old news. Everyone breaks the stocker and replaces with urethane because it's way cheaper and then they get the dreaded vibration. Do yourself a favor and go spend the $80-$90 for the OEM rubber mount before you start replacing everything else and discover it's just the mount. Heres more info by using the search:
https://ls1tech.com/forums/showthrea...smission+mount
https://ls1tech.com/forums/archive/i...hp/t-2947.html
This is a very common problem and only affects some cars. Why...who knows. Good luck!!

 

Not that its any help but i never broke the stock...then replaced it with the poly one and it only lasted me 3 weeks....i think im gonna stick with the stocker.

 

I put a prothane tranny mount, and motor mounts in my car. the only vibration I have is from the tranny scattershield rubbing on the floor a little.... but I'd rahter have that then something come thru the floor at my feet.

 

Cheaper wasn't the point of using a poly mount, and for your information I did replace the thing with a brand new OEM mount. It's not that damn hard to figure out where a vibration is coming from, I just didn't think all that shaking was normal coming from the drivetrain like it was which was the point of the post. Thanks for your helpful information.