Not sure if this should go in the trans or driveline thread but I will move it. I have had a vibration that seems that begins at 2500 rpm and is bad at 3000-3500rpm in drive and neutral but not in 1st or 2nd. It sounds like the car is hovering like a bad U joint or drive shaft. I took the driveshaft out and had it checked and the tubing was ovalled, so I had it retubed and balanced. Figured this was it but absolutely no difference. I changed the trans mount as well - no difference. Checked pinion angle. The converter is a 3200 rpm stall Car is a 72 cutlass with a 455 and a turbo 400. Is the trans going south or am I headed in the wrong direction ?