The 2.5-ton 6x6 light-heavy truck was known as the Workhorse of the Army. Over 800,000 vehicles were produced, most of them by the GMC Truck & Coach Division of General Motors Corp (562,750 units). The original GMC 2.5-ton 6x6 was the ACKW(X)-353 six-wheel drive commercial truck (1939-1941) which was also ordered by the French government.
Mass production of the military type started in 1941, and it quickly became the most widely used tactical transport vehicle of the US armed forces during World War 2. International Harvester produced a very similar vehicle for the US Navy and Marines, and more than half of the 197,000 units produce by Studebaker went to the Soviet Army. The 2.5-ton truck was available with a hard or soft cab, with or without winch. The soft cab version eventually became the military standard, and many of the existing hard cabs were later converted.