jtblckmaro

Hey guys, trying to isolate the cause of some vibrations and don't even know how to start a search on it, so here's what I'm thinking...
Heavy vibrations only when stopped at a light. (auto trans in drive)
As soon as I start rolling, the vibes go away.
Does not vibrate in N or P.
I'm thinking motor mounts because:
No applied resistance in N or P, but as soon as it's placed in gear, the motor wants to turn the gears in the trans... ( I'm a noob, so bear with the terminology, ok?)... placing a load on the motor, which the motor mounts can't handle, which causes the motor to vibrate.
Either that or I'm full of crap and have no clue (which is the one I'd go with).
Just did an oil change, plugs, wires, pcv valve, air filter, fuel filter.
I know this is VERY vague, but it's all I know to check.
So...
Anything I've missed? Anything else i can check? Any thoughts?
Thanks!

crasher88

sounds like mounts to me. Can you feel the vibrations in your butt while the car is sitting in gear or is it more in your feet, not trying to sound or be funny. Get a friend to break torque the engine. Have the set the e-brake firmly hold the break down and put it in drive and give it a lil gas then shift it into the reverse and give it a lil gas do it a few times and watch both motormounts and see how much they move. If the engine rock back and forth alot I would recomend replace the mounts. Now jack up the car and grab the tail shaft of the tranny and see if you can move the *** end of your tranny around any. If you can I would say replace your tranny mount as well. You can also just look at your mounts if they are dry rotted or severly cracked I would also recomend replacing them.

jtblckmaro

The vibrations are definitely in the seat. Had my wife do the gun it a little in gear with the brake set, didn't see any real motion. I'll jack it up and give my trans a wiggle though. And give the motor mounts a good visual.
Thanks for the reply.

zstine04

hey man sounds like what my 94 Z28 did i put 3 inch exhaust and it was vibrating against the small bolt on cross over. i just took it off.