I just changed my broken stock trans mount and replaced it with a prothane one from summit.. Prior to changing it i had 0 vibration and now i have one with this mount.. the vibration changes with rpm... even when it is not in gear ... ANYONE EVER HAVE THIS PROBLEM

 

lol, put the stoker back in.

 

I get many calls from people who after installing poly mounts they have vibrations etc. Theres as I have said many times a very good reason GM uses the rubber squishy mounts. What your feeling isnt really hurting anything but I am sure its anoying.

 

well i have talked to a few people like MATTD who has the same exact mount in his car with no vibration... its kinda weird... even in park it vibrates and varies with rpm

 

Some cars more some less and some none. There are lots of things that come into play. The poly mounts just transfer more of it if its there but in and of themselves they dont cause it.

 

I would recommend that you inspect your engine mounts if you have not already. Also, inspect the torque arm mount. If either or all of those are worn or broken then you will get a similar vibration.

Also, I have seen that the installation of the poly style mounts can bring to light another problem the factory rubber mounts hide... that is an out of balance driveshaft. But not likely as you feel it in neutral as well. You might consider removing yours and have it spin balanced at a reputable driveshaft shop in your area. Driveshafts are easy to neglect and can be a source of significant vibrations!

You might want to also check your pinion angle. I do not see any suspension mods in your sig, but if the axle housing has been changed or mods to the LCA's then it could be the source as well.... but not likely as you feel it in neutral.

Just some sources of vibrations to consider while chasing this issue. The Poly mounts can impart a certain amount of vibration through the body. But we rarely hear complaints, when we install mounts here we upgrade to poly mounts as they simply last longer.

Hope that helps.

g

 

I appriciate your gys help alot... im just hung up on this. when the car was bone bone stock i changed the converter and the stock mount to the prothane and noticed it then.. took it right back off and put the stock one on and it was fine...You guys think it safe for the track?

 

You changed the converter and mount at the same time? And this is when the vibration started, Hmm well the VIB could be coming from the converter if its a little out of balance possibly but since you changed them together its would be hard to say if its a vibration caused by the converter or a vibration amplified by the mount, I would suggest unbolting the converter and then rotaing and bolt back up and see if this has any effect. Other than that you could try putting the stock mount back in a see what that does. As for wether its safe for the track no one can say that for sure without knowing the source of the vibration and actually feeling how bad it is.

 

no about 1 1/2 years ago i changed the converter and put on the poly mount... took the car off the lift and test drove finding a vibration... Immediatl i changed the mount back to a stock one and have been fine since.. then saturady i broke the stoke one so i put the prothane back in and have the vibration back..

 

Ok... well if you are asking if the stock mount is suitable for track duty, the short answer is yes.

g

 

Agreed. I misunderstood your post, The stock mount will be fine as will the poly If you have been runing it this long I would not think the vibration is going to be and issue at the track.

 

No Frank, the man is saying he originally installed the aftermarket part and had a vibration. He then removed the aftermarket part, put a stock one back on and it was fine, no vibration, kept the aftermarket part. When the stock part again failed he agin put the aftermarket part on and has the same vibration he did some time ago.

You'll have to pardon Frank buddy, he has a lot of ground to cover and moves fast.

g

 

I understood what he said

 

ok this is getting really childish

 

This coming from a guy that one of the last times I saw you post here, posted "tastes like". Lets get back on topic here.

 

I had a very similar problem with a 95 lt1 found the problem to be a cracked flywheel. It was unnoticable with the stock mount with the poly-urathane it was very apperant, it made all kinds of vibrations.

 

Very good observation and I too have seen qiute a few cracked flex plates

 

Regardless once you start modding you have to compromise... I have my car lowered, poly mount, stall, supercharger, aftermarket pump, and a BMR Trak Pak... It can get a little annoying at times but I really don't mind because it's all worth it to me... for sure check the flexplate... That would be a bad thing to have it come apart...

 

if it was a flex plate though, when i momentarally put the poly mount in a year nd a half ago and had the vibration. i would have messed somethin up by now... Can a converter go out of round or make a vibration

 

True it would have shown itself likley by now if it was the flex plate. The converter could be out of balance but I dont think out of round, Now there are other sources You might consider, Harmonic balancer, Crank shaft. Its a little scary to do but with some help and care I really suggest a trans shop do it you could unbolt the converter and slide it back away from the crank and start car and feel for the vibe to eliminate all of that . Just i the converter starts turning shut down imdediatly , I have done this but its a little scarey if the pilots tight in the crank.