UNINTENDED REARWARD MOVEMENT OF 2000 M.Y. HUMVEE H-1 WHILE IDLING, WITH TRANSMISSION SELECTOR MID-WAY BETWEEN PARK AND REVERSE POSITIONS. VEHICLE HAD REMAINED STATIONARY FOR SEVERAL MINUTES BEFORE TRANSMISSION INTERNALLY SHIFTED INTO REVERSE, CAUSING VEHICLE TO MOVE REARWARD AT INCREASING SPEEDS, STRIKING A SECURITY FENCE AT 7- TO 10 MPH; THE FENCE & GATE TOPPLED ONTO SIDEWALK, STRIKING 3 PEDESTRIANS WALKING ALONG THE OPPOSITE SIDE OF THE FENCE. OUR ACCIDENT RECONSTRUCTION TEAM RECREATED EVENT SEQUENCE MULTIPLE TIMES -- WITH DELAY BEFORE MOVEMENT RANGING FROM SECONDS TO MINUTES. TRANSMISSION SHIFT MECHANISM OR INTERNAL VALVE BODY CONTROLS EVIDENTLY MIS-ADJUSTED. *NM