Trucktor, was a separate Company, from Truckstell. There was also, Truxmore, Grico, Fabco, & Detroit Automotive Products Corp., that supplied Chevrolet, with Tandem Axle Setups, on the Advance Design Trucks. Factory Assembly Line Tandems, were not available from Chevrolet, until 1956. The Trucktor Corporation, was out of, Mountainside, New Jersey. Here's a picture of the 1954 Chevrolet 5400 series COE, I had, that had the Trucktor Chain-Drive Tandem Setup,
http://community.webshots.com/photo/115981506/115990817iKfhhf
