ON I35 SOUTH BOUND JUST NORTH OF OSEOLA IA. AT 73 MILES AN HOUR SOMETHING CAME LOOSE ON LEFT FRONT CAR TOOK A HARD LEFT NO CONTROL CRASHING INTO CABLE BARRIER IN MEDIAN. 3 PEOPLE ON BOARD 2 FRONT 1 REAR. NONE CAN EXPLAIN WHAT HAPPENED IT HAPPENED SO FAST. LEFT FRONT WHEEL AND AXLE WERE NOT FOUND AT THE SEEN OF THE ACCIDENT LEFT FRONT WAS COMPLETELY GONE. ONLY 4 AIRBAGS OF THE 10 ON BOARD DEPLOYED. RECEIVED ONSTAR NOTIFICATIONS ON STABILITY CONTROL SYSTEM (STABILITRAK}, ANTILOCK BRAKING, ENGINE AND TRANSMISSION SYSTEM, AND FLAT DRIVERS SIDE REAR ALL AT THE SAME TIME.