An amphibious variant of the jeep, the Ford GPA, was also produced, but its flaws compared to other Allied amphibious vehicles led to its quick discontinuation. military during the war, replacing horses and other draft animals (still heavily used in World War I) in almost every role from cavalry to logistics, while improvised field modifications made the jeep capable of performing practically any other function necessary. The jeep became the workhorse of the U.S. As it became the primary light wheeled multi-role vehicle of the United States military and its allies, it became the world's first light four-wheel drive motor vehicle produced in 6-figure numbers.

Though early concepts were prototyped in the 1930s, the jeep's actual design and development took place in 1940–1941. Army had been requesting a small, light four-wheel drive vehicle since the early 1920s, because in World War One both motorcycles and sidecars plainly failed as mechanizations of the ridden horse in all roles.

Army Truck, 1⁄ 4-ton, 4×4, Command Reconnaissance, informally the Willys Jeep, Jeep, or jeep, and sometimes referred to by its supply catalogue designation G503, are American off-road four-wheel drive military light utility vehicles, built in large numbers to a single standardized design, for the United States and the Allies of World War II from 1941 until 1945. The Willys MB and the Ford GPW, formally the U.S.

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