roughneck9725

Hi all, just a quick question. I am getting a vibration at speeds above about 40. It gets worse when I let off and coast or push in the clutch and I can feel it in the clutch pedal. Just had the tires replaced (vibrated with old tires too) and the car has solid motor mounts but the vibration is speed related and not RPM related. Driveshaft? Yoke? Any ideas??

RabidSmurf

my guess is driveshaft you should try rotating it 90 degrees or 180 degrees.

roadrunner

need more info? driveshaft ,bent rim, ball joints , tierods. Is the front end tight? Go down the car and check for play in the struts and other items listed

My85QuarterHorse

Go out on the road, and get the car rolling about 15 MPH, push in the clutch and slide the gear shift from first to second back to first repeatedly, see if there is a "clunk" sound. If so, climb under the car and grab the driveshaft at the front and rear U-Joints and see if there is any play. If there is no clunking sound, then I agree with the previous poster...180 the driveshaft..and drive it.

If that doesn't fix it, check the crossmember under the tranny...if thats ok look for a missing weight on the drive shaft or a dent, or excess grime. If it gets worse when you push the clutch its because it is taking the tension off of it and allowing it to vibrate worse, when you get back on the gas it is tightning up a bit and reducing the vibration. Its without a doubt right there in that area somewhere.

If you cant find anything externally wrong...it could possibly be that your clutch disc is getting old and brittle and chunked a piece. If thats the case be EXTREMELY careful driving it, I had the clutch disc come apart in the 4 speed I had in my 64 Malibu...it all fell to the bottom got wedged and locked it up tight...right along with the back wheels, I was on I-75 running along at 65MPH, that was a wild ride, pushing the clutch didn't free it up. I came to a stop with the back end of the car hanging about 3 feet into the slow lane...I push the clutch the car would fire up, I was taching it up to 4500 and dumping the clutch trying to move the car, it would just kill the motor.

Id start with the U-joints...thats what it sounds like to me. Or somebody put U-joints on it and accidently 180'd it when they put the new ones on.