thE CLUTCH ISNT FULLY DISENGAGING, THATS WHY IT IS MOVING WHEN YOU CRANK IT UP IN REVERSE WITH THE CLUTCH PUSHED IN.

Most likely you have a bent pressure plate coupled with a torn up clutch disk.

Replace the clutch and it should run good as new. Drain the fluid out of the trans and look for metal shavings as well.

But what you are describing is a clutch issue, not a blown up tranny.