I WAS DRIVING MY FATHERS 2002 TOYOTA RAV4 AWD WHEN THE TRANSMISSION SUDDENLY SHIFTED FROM 2ND TO 1ST GEAR AND THEN THE DRIVE LINE LOCKED-UP CAUSING THE VEHICLE TO STOP SUDDENLY. A CAR FOLLOWING ME TRIED TO STOP BUT "TAPPED" MY REAR BUMPER. NO DAMAGE TO EITHER VEHICLE. DIAGNOSIS OF THE PROBLEM WAS A BAD VEHICLE COMPUTER AND NEW TRANSMISSION WAS NEEDED. COSTS WERE $4500. *TR