TL*THE CONTACT OWNS A 2004 CHEVROLET SILVERADO 1500. WHILE DRIVING 15 MPH WITH THE FOUR WHEEL DRIVE ACTIVATED, THE TIRES BEGIN SPINNING. THE FAILURE OCCURS WHEN THE GROUND IS SLIPPERY DUE TO MUD, SNOW, OR ICE. WHEN THE TIRES REGAIN TRACTION AND THE BRAKE PEDAL IS DEPRESSED, THE PEDAL WILL NOT GO DOWN AT ALL. THE VEHICLE REVS AND SURGES. THE ABS MOTOR CAN BE HEARD BUT THE BRAKES FAIL TO OPERATE. THE CONTACT WAS INVOLVED IN THREE CRASHES DUE TO THE FAILURE. THE FIRST CRASH DENTED THE DRIVER SIDE. THE SECOND CRASH OCCURRED WHEN HE STRUCK A TREE WHILE DRIVING IN REVERSE. THE BUMPER WAS BENT AND THE QUARTER PANEL WAS CAVED INWARDS. THE THIRD CRASH OCCURRED WHEN HE ACCELERATED AND THE VEHICLE REVVED AND SLIPPED ON WET GRASS. THE VEHICLE THEN WENT OFF THE EDGE OF THE ROAD AND DOWN 30-40 FEET INTO A SNOW BANK. A TOW TRUCK HAD TO RETRIEVE THE VEHICLE. THE VEHICLE HAS BEEN TO THE DEALER APPROXIMATELY 5 OR 6 TIMES, BUT THEY CANNOT DUPLICATE THE FAILURE. THE CONTACT HAS THE WORK ORDERS. THE CURRENT MILEAGE WAS 72,000 AND THE FAILURE MILEAGE WAS UNKNOWN.