I PARKED THE CAR & PLACED THE GEAR SHIFT IN PARK. THE ENGINE WAS STILL ON. I EXITED THE CAR TO MAIL A LETTER. THE CAR SUDDENLY ROLLED BACK HITTING A CAR THAT WAS WAITING FOR MY PARKING SPOT. THE ACCIDENT REPORT STATES THE CAR WAS "DRIVERLESS". I CONTACTED THE DEALER. RELUCTANTLY THEY EXAMINED THE CAR & SAID NOTHING WAS WRONG. I ASKED HOW WAS IT POSSIBLE TO EXIT THE CAR IF IT WASN'T IN PARK. MY FOOT WOULD HAVE TO BE ON THE BRAKE OR IT WOULD ROLL. SO I COULDN'T EXIT THE CAR WITH MY FOOT ON THE BRAKE!! OBVIOUSLY SOMETHING IS SERIOUSLY WRONG WITH THE GEAR SHIFT. IT HAS A MIND OF ITS OWN & SLIPS UNLESS THE ENGINE IS COMPLETELY SHUT OFF. I HAD NO WAY OF ENTERING THE CAR AS IT ROLLED TO PREVENT IT FROM HITTING ANOTHER CAR. IF I DID MOST PROBABLY I WOULD HAVE BEEN SERIOUSLY INJURED. TOWN & COUNTRY JEEP TOTALLY DISREGARDED MY COMPLAINT.