GMC offered single- or tandem-axle configurations for the trucks. You could spec a 702 cubic-inch GMC V112 gasoline engine, or your choice of Detroit Diesel 6V71 and 8V71 engines.

This second rear axle is designed to handle more payload for the full-size truck. This patent is targeting a non-permanent solution for a tandem rear axle. It looks like Ford might jump on the ...