The U.S. Army 2-1/2-ton series, 6x6 trucks were the most widely used tactical transport vehicle of World War II. Over 800,000 were produced, 562,750 by GMC alone. The first GMC 2-1/2-ton, 6x6 was basically a six-wheel drive commercial type, designated the ACKWX-353, which entered production in 1939. The French government ordered a sizable number of ACKWX-353s in 1939 which were diverted to the British when France fell to the Germans in 1940. Also in 1940, the AFKWX version of the 2-1/2-ton, 6x6 went into production. The code name AFKWX-353, translated as follows: A= 1939; F= forward control; K= front wheel drive; W= tandem rear axle; X= non-standard wheelbase; 353= 164-inch wheelbase. Early production models featured a pressed-steel, commercial cab and grille. As production progressed, the all-steel enclosed cab was replaced by a simplified cab, as displayed, with a canvas roof and side doors. The GMC AFKWX was produced in both a 352 version (145-inch wheelbase) and the 353 version, as displayed, (164-inch wheelbase). The 353 cargo body was produced in two lengths: 15-feet (as displayed) and 17-feet. The 6x6 GMC AFKWX series only accounted for 7,232 of the 562,750 GMC produced 2-1/2-ton trucks manufactured during WWII.