poly mounts chime in
 

About 2 weeks ago I replaced the motor mounts and tranny mount with poly replacements. Now I was expecting a decent amount of vibration to be noticed, but the vibration I have is almost unbearable. My entire center console and radio area on the dash sound like its going to come apart. This only happens after the car is warmed up and only in the 2200-2500 rpm range.

I was looking for input from anyone else that replaced these mounts and what kind of vibrations you are getting. Is this much vibration normal for this upgrade? Is there some sort of break in period for these? The stock mounts were absolutely shot and I could almost twist them in half.

I had these on my mustang back when I had that and the vibrations wernt near as bad, but then again I swapped those in placer of solid mounts, so anything was better than them.

Any input would be appreciated.

I didn't have the same problem but when I went to buy a poly mount for mine we noticed there were two part numbers for the same vehicle. We called pst and they said they made two different thickness mounts for whatever reason and you have to measure the one you have and match it or it will change driveshaft angle and cause crazy vibration. They were only about 3/8" difference from what I remember. I actually have one nib. When I get home I can check height and part number.

Thats strange. I ordered mine straight from energy suspension and they did not mention that. I know the drivers and passengers side are different from each other.

If you could post up when you are able to check that would be great.


When you say 2 part #'s do you mean for the trans mount? Cuz that I did run into, I got the newer part they made specifically for the 4th gens.

Did ya knock off a spark plug wire, or break a plug?

That I did check for. Everything in that dept is ok.

This. I noticed little change when going to poly mounts.

Yes there were two part numbers for the 4th gen. One was a little thicker. They told me to take it home and compare height. Ill post a picture later

Did the energy suspension trans mount come with a metal preload plate? They used to I assume they still do. I have seen people on other boards with the same issue and it was caused by the extra height of the preload plate. If it has one try removing it and see what happens.

Good call. I did put that in there when I put it all back together. I will pull that out and see if it makes a difference.

Pictures

Thanks for all the input guys, Im gona try a couple of things this weekend when I have time. Will report back with my findings.

you have the wrong transmission mount, the correct part number for the fourth gen camaros/firebirds is 3.1142. i bought mine from energysuspensionparts.com. i had the mount you currently have on mine, and it drove me insane, up until i read on here a thread about energy releasing the proper mount with the correct offset/height/angle for our cars. put the right one on, vibrations went away

I've been running poly/poly for a few years, with the ES mount without the preload plate on the trans. It was a little rough at first but after a few weeks it improved. Just recently however I threw a rubber trans mount on to see if it would quiet things down at all and it definitely did. Not going back to poly for the trans again.

You are incorrect sir. I do have the 3.1142g on mine now, but i put on the preload plate.

The problem is the poly mount is taller than the stocker and its throwing off your driveshaft angle. You need to shim shim the transmission cross member down 1/4" to 3/8". I have seen and fixed this on several cars.

Update**

I removed the preload plate and put in a newer trans yoke(the old one had the vibration dampener almost gone) and the vibrations are all but gone. Any vibration thats left Im chalking up to the poly mounts themselves being stiffer then my shot factory mounts.

All is good, thanks for the ideas guys!!

What was the trans mount part number?

3.1142g

Glad to see that got fixed. I have solids n love it