Since the WWII era Bantam Reconnaissance Car, the United States Army had relied on jeeps to transport small groups of soldiers. The jeep was built around a requirement for a compact vehicle with a folding windshield that was actually shorter than the Volkswagen Beetle. It seated three with a 660 lb (300 kg) payload and weighed just over one ton. By the 1970s, the U.S. Army had tried larger militarized civilian trucks, but even these no longer satisfied newer requirements. In 1977, Lamborghini developed the Cheetah model in an attempt to meet the Army contract specifications.
In 1979, the U.S. Army drafted final specifications for a High Mobility Multipurpose Wheeled Vehicle, or HMMWV, which was to replace all the tactical vehicles in the 1/4 to 1 1/4-ton range, namely the M151 quarter-ton jeep and M561 Gama Goat, as one “jack-of-all-trades” light tactical vehicle to perform the role of several existing trucks. The specification called for excellent on and off-road performance, the ability to carry a large payload, and improved survivability against indirect fire. Compared to the jeep, it was larger and had a much wider track, with a 16 in (410 mm) ground clearance, double that of most sport-utility vehicles. The new truck was to climb a 60 percent incline and traverse a 40 percent slope. The air intake was to be mounted flush on top of the right fender (or to be raised on a stovepipe to roof level to ford 5 ft (1.5 m) of water and electronics waterproofed to drive through 2.5 ft (0.76 m) of water were specified. The radiator was to be mounted high, sloping over the engine on a forward-hinged hood.
Out of 61 companies that showed interest, only three submitted prototypes. In July 1979, AM General (a subsidiary of American Motors Corporation) began preliminary design work. Less than a year later, the first prototype was in testing; Chrysler Defense and Teledyne Continental also produced competing designs. In June 1981, the Army awarded AM General a contract for development of several more prototype vehicles to be delivered to the government for another series of tests. The original M998 A0 series had a curb weight of 5,200 lb (2,400 kg). with a payload of 2,500 lb (1,100 kg), with a 6.2 L (380 cu in) V-8 diesel engine and a three-speed automatic transmission.
The three companies were chosen to design and build eleven HMMWV prototypes, which covered over 600,000 miles in trials which included off-road courses in desert and arctic conditions. AM General was awarded an initial contract in 1983 for 2,334 vehicles, the first batch of a five-year contract that would see 55,000 vehicles delivered to the U.S. military, including 39,000 for the Army; 72,000 vehicles had been delivered to U.S. and foreign customers by the 1991 Gulf War, and 100,000 were delivered by the Humvee’s 10th anniversary in 1995. Ft. Lewis, Washington and the 9th Infantry Division was the testing unit to employ HMMWV in the new concept of a motorized division. Yakima Training Center in Yakima, Washington was the main testing grounds for HMMWVs from 1985 through December 1991, when the motorized concept was abandoned and the division inactivated.