 In 1939-1940 the US Army Ordnance Corps was developing a -ton (5,000lbs, 2,300kg) load-rated 6×6 tactical cargo truck that could operate off-road in all weather.Dump, semi-tractor, tanker, and other bodies were also planned.Yellow Coach (a GM company), Studebaker, International Harvester, and REO submitted designs, all except REO's were accepted and in production by 1941.