THE TRUCK WAS PUT INTO PARK WITH THE KEY IN THE IGNITION AND THE ENGINE RUNNING. IT WAS PARKED IN A RESTAURANT PARKING LOT. THEN AROUND FIVE MINUTES LATER, IT WENT INTO REVERSE AND BEGAN ROLLING BACKWARDS. IT SEEMED TO ACCELERATE. I HAD TO JUMP IN AND SLAM ON THE BRAKE TO STOP IT. I DO NOT KNOW HOW THIS COULD OCCUR, BUT HAVE RECENTLY LEARNED OF RECALLS FOR SIMILAR SITUATION WITH THE TRUCK IN THE PARKED POSITION, BUT GOING INTO GEAR. OUR VIN WAS NOT RECALLED. THERE WERE WITNESSES TO THIS EVENT.