HELP polly tranny mount vibration

[vecaj]

Well, this is my first post, im lookin for a little help. I have a 4A trans am with a cold air and jet chip. I broke my factory tranny mount, got it replaced, and broke the new one about 2 months later. I got the polly mount from thunderracing, and got it installed today. Now I have this midly bad vibration, expecially around 1800 rpm. The mechanic who put it in said because of the stiffer mount I can feel more vibration, but I dont know... it just doesnt feel right. I didnt throw a code, and it still drives alright, but I want to make sure that im not hurting my car, ya know? Should I replace both motor mounts? maybe my strong mount is putting more pressure on them? The thing I dont understand is it makes the vibration even if it isnt in gear and I rev it up. I dont know... help me out... im getting a tune up next oil change, maybe that will help some...
thanks

-Josh
:wtf:

[mrr23]

the mechanic is correct. the stiffer poly mount will transmit more drivetrain vibration. one thing to take some of it away, is to remove the metal bar they say to put inbetween the mount and trans. next, would be to grind the two humps down flat.

[vecaj]

The polly mount makes it vibrate even when its not in gear, does that sound right?

[Ed Blown Vert]

From what I understand, poly will transfer alot of vibration. Which is why I replaced mine with with a stock mount.

[02WS6dream]

Good to hear someone else is wondering about that! I also installed a poly mount about 2 weeks ago and have wondered why i am now experiencing vibration even when in park and revving. Thought maybe something else was broke, and could just feel the vibration it was causing because of the stiffer mount. Pretty annoying vibration rolling down the road too--especially at high speed. How do you keep from breaking your stock mount 'ed'??? Just replace it often???

[mrr23]

yes, it transmits every little movement from the engine/drivetrain as well.

[vecaj]

so it wont hurt my drivetrain any, right?

[mrr23]

no.

[cruz3]

I had mega vibration when I changed to the poly. I had my driveshaft balanced and it isn't bad at all anymore. I would definitely recommend balancing if you haven't done it yet and/or if you have replaced the u joints.

[02T/AWS6]

if you're gonna have the polly tranny mount than you should get matching polly motor mounts if you don't you will get a bad vibrations due to having differnt mounts , however u will still get some vibration even if both are polly but its will be better on the car , don't mix and match mounts, stay consistent with what kind you use, i tried to change only my tranny mount and found this out the hard way

[Ed Blown Vert]

if you're gonna have the polly tranny mount than you should get matching polly motor mounts if you don't you will get a bad vibrations due to having differnt mounts , however u will still get some vibration even if both are polly but its will be better on the car , don't mix and match mounts, stay consistent with what kind you use, i tried to change only my tranny mount and found this out the hard way

I actually had good luck with the poly engine mounts and the stock tranny mounts.

[02T/AWS6]

I actually had good luck with the poly engine mounts and the stock tranny mounts.

thats interesting, maybe its cuz you had stock tranny and poly motor mounts i had it the ohter way, polly tranny mount and stock motor mounts, thats good to know

[cruz3]

What happened with the Poly tranny/stock engine combo? Tailshaft housing crack?

[02T/AWS6]

What happened with the Poly tranny/stock engine combo? Tailshaft housing crack?

nothing broke, probably because i didn't leave it like that for a while, but using that combination i had really bad vibrations

[cruz3]

I think the poly tranny mount emphasizes problems in the driveshaft. I spent $65 getting my driveshaft balanced since my local dealer didn't care if it was/wasn't when they fixed the front yoke, and it is very smooth. Of course, now my tailshaft has a lot of play in it, so I'm sure that will need to be replaced sooner than later. All of my goofing with this started with a clunk and I'm pretty sure the tailshaft bushing was shot and my dealer failed to diagnose it.

[02T/AWS6]

good point