I have poly motor mounts and poly trans mount installed on my car. I know that its normal to feel more vibrations than with the stock rubber ones, but what I'm not sure about is that when I"m shifting there is some sort of vibration/grinding type feeling through the shifter when the car is in motion. It happens in between gears after pushing the clutch in. Is this normal or are the mounts causing some sort of alignment issue? Hope this makes sense.
Yes I searched.

 

Only way new mounts could cause your transmission to grind is if the trans isn't bolted securely to the engine.

 

Sounds like worn syncros IMO.

 

My 93' also has this strange vibration issue also. Did you have this issue before your poly mounts? If you did, my buddy (Old timer GM cert. tech) thinks perhaps an engine/trans thrust angle issue here and recommends shimming poly-trans mount-engine mount to find correct angle and also to square-off the transition to driveshaft. He remembers a GM recall back in 1994 for this particular issue...

 

No this wasn't an issue before the mount change. It sounds like the angle could be off, but I'm not sure any more opinions out there? If it is the thrust angle then how would I go about checking that and fixing it?

 

And now I do remember, after changing the trans mount and grinding off the bumps (Energy Suspention tranny mount) the mount was still maybe a quarter inch thicker than the stock rubber mount. So to compensate I added washers between the trans crossmember and the car.

 

My buddy shimmed mine and the vibration went away. I wasnt there to see him do this but he did use a magnetic angle finder and ended up using a shim plate for the passenger side engine mount to fix issue...it worked though! It's been awhile, there might have been other stuff he did. He had my car all day.

 

I see, so he shimmed the motor mounts?? Hopefully someone will come in with recommendations on how to do it. This sounds like my problem..

 

I used the factory housing with the Energy Suspension poly mounts, thinking the factory mounts were worn. The vibration was still there. Ultimately I took my Camaro to my GM buddy where he fixed my issue.

 

Try a Prothane poly trans mount instead of Energy suspension...I have a Prothane one with no issues; they only cost $20.