I PUT MY 2010 NISSAN FRONTIER TRUCK INTO FOUR WHEEL LOW TO BACK MY CAMPER INTO ITS PARKING AREA. THE PARKING AREA IS LOCATED AT THE TOP OF A SLIGHT INCLINE. AFTER BACKING THE CAMPER INTO POSITION I PLACED THE TRUCK INTO PARK AND LEFT IT RUNNING WHILE I SECURED THE CAMPER BY PLACING CHOCKS BEHIND ITS WHEELS AND PUTTING A FOUNDATION FOR THE JACK. I REMOVED THE SAFETY CHAINS AND THE HITCH LOCK FROM THE CAMPER AND JACKED IT UP. AS THE HITCH CAME OFF THE TRUCK BALL THE TRUCK BEGAN TO ROLL DOWN THE HILL FREELY. I WAS UNABLE TO CATCH IT BEFORE IT STRUCK THINGS IN ITS PATH AND FINALLY CAME TO REST HITTING A TREE. THE TRUCK WAS STILL IN PARK BUT THE INDICATOR FOR THE 4 WHEEL DRIVE AND VDC WAS OFF. THE TRUCK WHEN PUT N REVERSE WOULD NOT MOVE. I TURNED IT OFF FOR A FEW MINUTES AND RESTARTED IT ACTED NORMAL. *TR