CAR WAS PUT INTO REVERSE FROM PARK IN DRIVEWAY. WITH BRAKES STILL APPLIED, ENGINE RACED AND TIRES BEGAN SPINNING. CAR RACED IN REVERSE APPROXIMATELY 50 FEET,HITTING ANOTHER VEHICLE AND CAUSING DAMAGE TO BOTH VEHICLES. DRIVE SHAFT NOTED HANGING FROM VEHICLE. CHRYSLER MECHANIC REPLACED REAR DRIVE SHAFT, DIFF. YOKE, THOUGH REPORT "NO HIGH IDLE CONDITION FOUND" AND THAT "THROTTLE BODY IS OPERATING CORRECTLY". MECHANIC DID EXPLAIN THAT THE CAUSE OF THIS TYPE OF INCIDENT AND DAMAGE TO DRIVE SHAFT COULD BE ENGINE RACING WHILE BRAKES STILL APPLIED. *AK