TRUCK WAS IN PARK. PUT MY FOOT ON BRAKE, SHIFTED INTO DRIVE, TRUCK IMMEDIATELY MOVED FORWARD WITH FOOT STILL ON BRAKE, AT APPROX 2- 5 MPH. PUSHED CONTINUALLY HARDER ON BRAKE WITH NO RESPONSE. LIFTED FOOT COMPLETELY OFF BRAKE AND PUSHED AGAIN, THEN TRUCK STOPPED. WENT THROUGH A GARAGE DOOR IN THE PROCESS, COULDN'T STOP UNTIL TRUCK WAS FULLY THROUGH.*AK