new poly trans mount, vibration issues .
 

ok, well i just put the trans mount in, its a energy suspension poly mount. i noticed that the mount was a little taller than the old one, and it was a tight fit to bolt on the crossmember, maybee pushing up on the trans?

i just got back from driving the car, I can tell the new mount is much stiffer just from turning the car on.

anyway the thump went away, and it shifts great, but i can tell there is much more vibration around 3000 rpm's or above, is this normal with a poly mount?

when it shifts it gives me a boost like never before, i have an auto with shift kit and valve body upgrade, and i still heard a chirp in 3rd gear, thats how much different it is.

i like the extra performance and all, but i dont want to hurt the car, I was wondering if i should go with the OEM style mount, or if the poly mount just needs to be broken in?

RE: new poly trans mount, vibration issues .
 

Sorry I cant help with the current problem, getting ready to do the same thing with my 94, did you run into any problems putting the mount on, tips? Where did you buy the poly mount, how much? Thanks man!



akohnz

RE: new poly trans mount, vibration issues .
 

Personally I like the stock mounts, mainly because I don't need to get arse massaged as I drive around. I have no objection if he car was used only for racing. However, they won't harm your car, but may loosen a few screws here and there.

RE: new poly trans mount, vibration issues .
 

Ok, so the vibration is normal?, pete- the mount was taller than the stock mount, so i figured when i bolted the crossmember on it put upward pressure on the trans and thats what was making the vibration .

akohnz- getting it off wasnt bad, put the back of the car on jack stands (i used the control arms), jack up the trans an inch or so and unbolt the 4 crossmember bolts and the 1 transmount bolt then the crossmember comes right off, there should be 2 5/8ths bolts holding the stock mount shell on, get those off and your ready to put the new one on.

when you put the new one on they give you a shim that must be used directly on the trans, put the bolts through the mount, and then the shim and into the trans.

PETE - this part is what i was referring to, putting the crossmember on,

i noticed that the new mount was longer than the old one, after putting the first side the crossmember with 2 bolts in there was a gap in the other side, i loosened the first side so i could get the other side in and then tightened them all, after i had it all bolted on i noticed that i could move the jack, it had pushed the transmission up a hair higher than i had jacked it!!!

is this a bad thing? i thought thats why it was vibrating so much, so at work today i made up 4, 1/4 gauge steel 2inchx2inch shims with 3/8ths holes in the center to use as a spacer with the bolts, on the top of the crossmember to level things out, should i try this or is it fine the way it is?

RE: new poly trans mount, vibration issues .
 

You have two reasons for the vibration. The main reason is that the poly mount although stronger than the stock mont is also much stiffer and does not absorb engine & transmission vibrations too well. The other reason is, if the poly mont is really taller than the stock mount ( the stock mount may have deformed due to age) then it will change the driveshaft angle and cause slightly more vibrations at steady speeds. In any event, nothing is going to get damaged, but the vibration could get annoyng.

RE: new poly trans mount, vibration issues .
 

you are the man pete, what would camaro forums do without ya!

RE: new poly trans mount, vibration issues .
 

Thanks for the info and replyin, you and Pete are awesome!


akohnz

RE: new poly trans mount, vibration issues .
 

I am going to replace the motor mount with tranny mount at the same time, do you have any pointers on replacing the motor mount? Got a 94 z28, when I replace the tranny mount should I do the cross member also?


akohnz

RE: new poly trans mount, vibration issues .
 

It is a very good idea to replace all the mounts, engine, transmission, and torque arm, at one time as they all work as a unit. The transmission mounts sits on the crossmember, and the torque arm mounting/bushing is attached to the transmission tailshaft. Also if you been working the car hard, this is a good time to inspect the torque arm for cracks, loose bolts, etc..

The way I get to the engine monts is:
1)Unscrew and remove the through bolts holding the mounts to the frame brackets .
2)Unbolt the transmission mount from the crossmember.
3)Lift front of engine 1 or 2 inches to make room between the engine and the subframe.
(I like to use a pece of 2X4 with cleats on the ends and palce it under the front pulley, and slowly raise the engine with a jack. Also, as a percaution, I like to have a transmission jack snugged up under the oil pan to keep the engine off my fingers in case the front jack should slip off and let the engine drop. Do not use the jack underthe oil pan to lift the engine)
4)Unbolt the mounts from the egine block.
5)Relace engine mount
6)Replace transmission mount
7)Replace torque arm mount/bushing
8)Put everything back in the opposite order

RE: new poly trans mount, vibration issues .
 

Thanks for the info Pete. I was doing some reading on replacing the motor mount and I came across a section that said the rivits had to be drilled out and part of the motor mount had to be welded back on, I was looking at the motor mounts and it looks to me that everything should bolt up. Also I noticed that whenever my engine is idling it almost pulses and the engine itself shakes, obviously the engine is going to vibrate, but you can physically see the engine move. Will replacing the motor mount fix this? Thanks again for your help, you really have no idea how much you have helped me out.


akohnz