The driveshaft, does have weights, just like your wheels would/do. If they fall off, or become rusted, they can basically make the driveshaft attempt to go in an oval motion, instead of a nice smooth circle. That might be your guys' problem, but I don't see how that would only affect me in a 8-10mph range.jpi99 said:What from the driveshaft was causing it to have a vibration? How did you fix it?