During the late 1970s, the US military decided to replace many mission-specific type vehicles such as the M151 MUTT and M561, with a standard 4x4 vehicle. As a result, they designed a vehicle that was reliable, versatile, and had excellent off-road mobility. The vehicle was comprised of an aluminum body and steel frame. It also featured a 4-wheel independent suspension, and 150hp V8 diesel engine. These versatile vehicles were used for a wide variety of tasks such as cargo/troop transporter, ambulance, and armament carrier. The �armament carrier� was equipped with either a Mk. 19 grenade launcher or a M-60 machine gun. U.S. forces were issued these vehicles in 1985. The 4x4 vehicles were first used in Panama in 1989.