The contact works for a trucking company that owns a 2004 Ford F-650 SD 3-Ton Commercial Vehicle. The contact stated that the gear shifter rubber boot was not securely mounted onto the floorboard, resulting in a gap that allowed the driver to see underneath the vehicle. The contact stated while driving at various speeds, there was a strong engine oil odor and carbon monoxide odor entering the cabin through the gap in the floorboard. The contact stated that he had headaches due to the failure. The contact notified an independent Diesel mechanic of the engine oil leak, but the mechanic declined to diagnose or repair the vehicle. The mechanic informed the contact that the vehicle was no longer safe to drive and should no longer be driven on the road. The vehicle was not repaired. The dealer and the manufacturer were not notified of the failure. The failure mileage was unknown.