1972 Scamp 318 Auto, been sitting for ten years. It had this same vibration during the Bush years, but it went unsolved.
I just had the rearend rebuilt (3.55 Posi). It was howling, and I thought it might take care of the vibrations too. It took care of the howling and some of the vibrations, but...
The car thrums, vibrates, rhythmically at 3500 rpm in multiple gears. It's really pronounced in the dash for some reason.
My friend, who I bought the car from, thought it might be the torque converter, which he had pulled out of 1976 dart cop car; the transmission was rebuilt at that time, but not the TC. This was 15 years ago.
I have done a little research, and it could be:
Alternator out of balance
Powersteering out of balance
Harmonic dampener failed
Rotating assembly unlikely
Flywheel out of balance
Torque Converter fail?, out of balance?
Am I missing anything? There's not a lot of threads on the net, doesn't seem to be common problem.
He told me to wait for **** to blow up, which is what he was doing. I think this thrumming vibration is doing bad things to the rotating assembly, and even after the motor goes, the problem will still exist. I'd like to solve this. How do I figure out where it's coming from? What's the best order? I would rather diagnose than just start throwing money at it.
Scamp has urethane motor mounts. I doubt the transmission mount is also urethane.
