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HMMWVs: When Lightweight Utility Vehicles Just Don’t Cut It

The Vietnam-era M151 series jeep was an upgrade from the Willys M38A1s and a tremendous success in the U.S. military for many years; it was more versatile and reliable than the earlier jeeps, but it had its issues. Due to its lightweight design and a faulty swing-axle rear suspension design, the M151s were prone to rolling over while cornering, forcing soldiers to place ammunition boxes full of sand in the back when the jeep was not loaded to weigh it down for better maneuverability. Up until the mid- to late-1980s, Ford’s LUV design reigned over all, but the many Army accident reports on lightweight trucks prompted the U.S. military to invest in a faster, safer alternative that was more dependable, durable, and powerful. This need resulted in the High Mobility Multipurpose Wheeled Vehicle (HMMWV).

The HMMWV, commonly referred to as “Humvee,” was the best solution to a number of issues facing the American military that eventually phased out the M151 jeeps.

The Coming of the Giants

In 1979, three companies submitted prototypes for a  jeep. ¾ ton and 1 ¼ ton replacement that met the specifications of the military. The HMMWV would need better performance on- and off-road, the ability to carry heavy equipment, and increased survivability for consideration. AM General (a subsidiary of AMC) clinched a preliminary contract in 1981 and began producing additional prototypes for military and government testing. Soon afterward, in 1983, AM General was awarded an official 5-year contract for over 2,000 HMMWVs and resulting in over 55,000 to be delivered to the  Army.

At first, the Humvees were not entirely prepared for combat and military use, but extensive testing throughout the mid-80s led to outstanding success. Their many viable assets included:

●     Wide body & track (for all-terrain maneuvering and speed)

●     Weight (5,200 lbs)

●     150 horsepower (6.2-liter diesel V8 engine)

●     High-mounted differentials for better ground clearance 

●     Allison three-speed automatic transmission

In 1984, the A2 variant increased the engine to 6.5 liters, resulting in 160 horsepower at 3,400 rpm. The Allison three-speed was replaced by a four-speed model.

HMMWVs first saw combat during the U.S. invasion of Panama in 1989. After Panama and Operation Restore Hope in Somalia in 1992-1993, the military recognized that the unique urban warfare required better armor against small-arms fire and added survivability. The AM General M1114 was designed to meet those requirements. Humvees were also sent to Afghanistan after the 9/11 terrorist attacks in 2001 and proved their mettle successfully. However, after IEDs became more prevalent at the onset of the Iraq War, these giants were sorely vulnerable. Armor kits were installed on many Humvees that made the vehicles unwieldy and much heavier.

HMMWVs were and still are invaluable military vehicles that help protect our freedom. To learn more about HMMWVs or to buy CJ3B engine fuel or schedule a steering box repair service for your jeep, Call Army Jeep Parts today!