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. In 1941, the militarized version of the 2-1/2-ton 6X6 went into production. Code named CCKW-353, which translated as follows: C=1941; C=conventional cab; K=front wheel drive; W=tandem rear axle; 353= 164-inch wheelbase. Early production models featured a pressed steel, civilian style, rounded cab. As production progressed, the all steel cab was replaced by a simplified cab, as displayed, with a canvas roof and side doors. The GMC “Jimmys” made up the bulk of the famous Red Ball Express which operated across Northern France during the fall of 1944. With most railways out of action, the U.S. Army organized a massive “road lift,” involving over 5,400 trucks averaging a daily delivery of 5,143-tons. Studebaker and International Harvester also manufactured 234,000 of the 2-1/2-ton 6X6 trucks.