Ok so this basically started when I was using the car as a daily for a while. I had to go down a very crappy bumpy road everyday to get to work. Every time I now drive the car over a bumpy road it sounds as if the rear end of the car is moving around, or the wheels are going up and down. Something back there is shaking/moving and I dont know what. When I'm driving the car I can feel a weird vibration, it's sounds as if when one of the shafts is spinning its hitting something as it spins or something. Another thing whenever I drive the car in the rain, ( I never do but if I HAVE to ) after a while the whole car starts vibrating/shaking. Was pretty scary when I was taking my girlfriend to dinner when it was raining one night and the whole car started vibrating. The car has a built C9 auto and all the rear bushes have been changed to nolathane bushes.