I would like to know what you find out. We had a 79 one ton tow truck that sounds like the same problem. It was called the death shake. Going along at 30 mph, hit a small bump and hold on. The whole truck shook. The steering wheel would turn back and forth really fast. You have to stop the truck to get it to quit. We checked everything underneath and could not find anything wrong. The truck is only used in the yard now, but would like to know what is wrong. :confused: :confused: