ZL1Killa

iTrader: (17)

from idle to ~70mph car seems fine. 75mph~80mph+ the whole car vibrates. The rear view mirror vibrates so bad you cannot make out cars. The e-brake spring in the center console resonates also. When accelerating it is not as bad, but when holding a steady speed it seems worse and gets really bad when clutch in and slowing down.

I would think something rotational.
I've replaced:
*Both front wheel bearings
*axle bearings
Tires are brand new & balanced, even had them re-checked after they said they were balanced and I watched them.

Only thoughts are something relating to the transmission. I do have a cross-member mounted torque arm, so I know some more noise/vibration will come from this, but I know what I'm feeling is not normal.

Thoughts, ideas?

Brennen's01SS

iTrader: (1)

ID suggest getting the tires road force balanced. I went through this awhile back with new tires. Some suggested road force and it cured the problem. Most Cadillac dealers have them.

ZL1Killa

iTrader: (17)

rode with a friend in the car and the vibration wasn't as bad. thinking driveline angle and/or u-joints.

Ben Mynatt by my house offers it..will check out.

great421

iTrader: (1)

Another poss root cause to your vibration - the driveshaft.

ZL1Killa

iTrader: (17)

yep. It was checked when I bought it...but there is no telling.

QuicksterZ

iTrader: (2)

driveshaft,motor mounts maybe, wheels not torqued correctly

JDEP162

im a tire noob, what is road force balance? sound like balance where its on a roller?

07kyeringt

Honestly I would start with basics.. alignment. Otherwise it may be mounts or some bad bushings.