THE AUTOMATIC LIFTGATE OPENED NORMALLY AND MOMENTS LATER FELL SUDDENLY AS THE OPERATOR WAS PLACING ITEMS IN THE VEHICLE. THE LIFTGATE STRUCK THE OPERATOR ON THE HEAD CAUSING INJURY NOT REQUIRING TREATMENT. THE LIFTGATE WAS CLOSED AND LATCH ENGAGED BEFORE THE VEHICLE WAS IN MOTION. WITHOUT WARNING THE LIFTGATE MOTOR ENGAGED WHILE THE VEHICLE WAS DRIVING AT A HIGH RATE OF SPEED AND THE OPERATOR SUFFERED PROPERTY LOSS. THE OPERATOR PULLED OFF THE HIGHWAY AND ATTEMPTED TO SECURE THE LIFTGATE BUT WAS UNABLE TO GET THE LATCH TO ENGAGE. THE OPERATOR CONTINUED TO DESTINATION CAUTIOUS WITH THE LIFTGATE OPENED. ONCE THE VEHICLE WAS STOPPED, THE OPERATOR WAS ABLE TO CLOSE THE LIFTGATE AND ENGAGE THE LATCH. THE LIFTGATE WAS SECURE WHEN THE OPERATOR PROCEEDED TO ENTER THE BUILDING. SOME TIME LATER, THE OPERATOR WAS NOTIFIED BY A CO-WORKER THAT THE VEHICLE LIFTGATE WAS OPENED. THE RECENTLY REPLACED STRUTS ARE NOT SUPPORTING THE LIFTGATE AND IT FALLS SUDDENLY ON THE OPERATOR. THE LIFTGATE OD ALSO ENGAGING WITHOUT OPERATOR INITIATING THE ACTION, EVEN WITH THE VEHICLE IN MOTION.