MY RAM TRUCK WAS PARKED IN MY DRIVEWAY. I WENT OUT AND STARTED MY TRUCK, WENT BACK INSIDE THE HOUSE TO GATHER MY THINGS APPROXIMATELY 2-3 MINUTES. WHEN I CAME BACK OUT TO MY DRIVEWAY MY TRUCK HAD STARTED TO ROLL DOWN THE DRIVEWAY AND ENDED UP CRASHING INTO MY NEIGHBORS FENCE. THE TRUCK WAS IN PARK WHEN STARTED AND SOMEHOW CAME OUT OF GEAR OR HAD A COMPUTER FAILURE ON THE ROTARY SHIFT KNOB. THE DIAL INDICATOR WAS STILL IN PARK WHEN I ENTERED THE VEHICLE AFTER THE ROLL AWAY.