I have a 1964 Buick Rivera with the 425 engine automatic.

Question:  It has a driveline vibration which starts as I accelerate is worst at 30 mph to 50 mph then dissipates at higher speed. I have had the driveshaft balanced and it had no effect. Tires are new. Universals seem good. Can you give me any advice as to what might be causing the vibration?

Answer:  We think your drive shaft is a two piece unit with a CV style ujoint in the center and rear. From you description of the problem we would suspect that your center bearing is worn out or you possibly have a broken transmission mount.

The center bearing is our part number PFPT3R80-10 you can see it in the image, rubber is probably gone bad.  If the center bearing is worn out give Lance or James a call at 800-444-0755 they can help you with a replacement.

You can see the center bearings we off on our site at:   http://www.provenforce.com/center_bearing/gm_chevyi_center_bearing.html#

If its not the center bearing you should consider sending the driveshaft complete (both halves) to us for checkout, we will provide an estimate to repair.