ON AT LEAST TWO OCCASIONS THE JEEP GRAND CHEROKEE ROLLED AFTER THE SHIFTER WAS PLACED IN PARK POSITION. !. ON 11/18/2013 DOOR WAS AJAR WHILE DRIVER WAS ABOUT TO TURN OFF VEHICLE. JEEP SLIPPED OUT OF PARK AND SLOWLY BACKED INTO A CONCRETE BUTTRESS AT A GAS STATION CAUSING $900 DAMAGE TO THE DRIVER DOOR AND FRONT QUARTER PANEL. 2. IN THAT SAME WEEK, SHIFTER SLIPPED OUT OF PARK WHILE DRIVER WAS BEHIND VEHICLE TAKING A PHOTOGRAPH. SERIOUS INJURY PREVENTED BY PASSENGER WHO PUSHED THE SHIFTER BACK INTO PARK. VEHICLE TAKEN TO DEALER FOR THIS PROBLEM ON 11/22/2013. DEALER INSPECTED AND HAD INSPECTION BY CHRYSLER FIELD REP. BOTH DENIED PROBLEM. SEE ATTACHMENT. THE PROBLEM CONTINUES. IT IS NECESSARY TO CAREFULLY INSURE TRANSMISSION IS IN PARK BY HOLDING GEAR SHIFT IN PLACE.