Violent shaking in reverse with T5 trans

Is it clutch chatter? If not you might check the rear springs, they could be weak or broken and are twisting when backing up...

maybe a broken trans or motor mount?

ditto bill

Thanks guys. I thought about the mounts. Looked under the car and the motor mounts 'look' fine. I didn;t see any signs of seperation. The motor does not have any excess movement when the throttle is winged, unless the mount under compression is broken. I didn't check his trans mount. I would guess that it would be new. Rear springs look ok. It's definately pretty violent, especially backing up a slight incline. I was also thinking U-joints.

Again, thanks

I had a work pickup that started doing the exact same thing - as a matter of fact, it got to the point that I could not even back up any type of incline. I had to take the truck in and the transmission was adjusted. I think some of the bands were out of adjustment. Fortunately the truck was under warranty, so I have no idea of costs.
You might check with a reputable transmission shop.

and while im thinking of it, if the clutch disc has springs in its huband theyre damaged, the disc could chatter.

I'm still leaning towards a motor mount....I've had a broken one that didn't show up until I moved the car with the hood up (maximized engine twisting forces....it wa an auto and I "brake jacked" it