Federal Excise Tax on Trucks, Truck Bodies and Trailers The federal excise tax (FET) is a 12% sales tax imposed on the first retail sale of truck, trailer, and semitrailer chassis and bodies, and tractors (trucks over 33,000 lbs. GVWR, tractors with a GVWR over 19,500 lbs. and have a gross combined weight, in combination with a trailer or