The M151 series (aka the MUTT) was the final line of Jeeps produced for the US Military. Developed throughout the 1950s to replace the M38 and M38A1 models, the M151’s chief improvements were its semi-monocoque design and independent suspension. While the new suspension increased the vehicle’s cross-country capabilities, it presented a perilous flaw that lent itself to roll-overs when turned too quickly on paved roads. The M151A2 tried to remedy this with a semi-trailing arm suspension, though with untrained drivers the risk still existed. Despite this flaw, the M151 series performed well in the field, lasting officially from the Vietnam War and into the 1980s.