Tank2260

Alright, I have a 2002 Trans Am, Automatic w/about 60,000 miles. The car is stock besides cat-back, intake, and wheels. I get good amount of vibration sound (from under dash) and feel (in gas pedal) at 1100-1300 rpms when in gear. Doesn't do it in nuetral or park.

I checked the harmonic damper, seems to be on there solid. Driveshaft seemed alright. Tranny mount looks/feels fine. Not sure what it could be... don't want to get charged an arm and leg at a shop for them to chase the vibration down.

Any thoughts...?

JaYZeig

iTrader: (11)

is this while your brake torquing im assuming?


possibly torn rubber engine mount, somthing contacting the body of the car from the drivetrain,

Tank2260

No brake torquing, just under normal driving...

Thanks for the input. Any easy way to check the engine mount?

Any other possibilities?

Tank2260

any other opinions??? with a ten year old car... worth it to just go ahead and replace the motor mounts and u-joints?

1ltcap

what speeds?

take the driveshaft out to check the universals. often, they'll sorta seize. when this happens, they'll feel good if you only grab the driveshaft and wiggle. they can, and will cause vibrations though. it was common like that on ford vans in the 80's.
other thing to check, is tires for balance, transmission mount,

Tank2260

Thansk for the suggestions.

It is not speed related, but RPM related. 1,100 - 1,300 rpm range when in gear. I can feel the slightest thing when in park and bring it up to that rpm range... but I might be psyching myself out now haha.

1ltcap

wait.....only at that rpm? regardless of speed? it only has to be in gear? is it a steady vibration, or could it possibly be something like an erratic misfire doing it? i ask, because i've seen egr's open too soon, creating a lean misfire. i'm kinda drawing straws on that one, but it could be something to check.

Tank2260

Correct, only at that rpm range. I would describe it as a steady vibration... engine is not choppy like I would expect from a misfire.

1ltcap

a lean misfire like would be caused by too much egr, would be more of a "flutter". kind of erratic.

if this is steady, and only at that rpm, and only in gear, then it would have to be something inside the transmission, even if it's doing it when not moving, but torquing to that rpm.

this is a tough one. the tough ones are fun.

Tank2260

Haha fun, good word choice. Although fun generally = PIA and $$$

Thanks for you help, I might break down and bring it into a shop this weekend...