Since its initial introduction in 1985, the High Mobility Multipurpose
Wheeled Vehicle (HMMWV) has undergone many changes and improvements to
meet military requirements. Because the HMMWV can be modified in so many
ways from one basic platform, there are many different models and configurations.
The military generally refers to HMMWVs as M998A0, M998A1 or M998A2
series. Different models actually have different designations but share
the same frame, suspension, and drive train geometry and the same hood
and lower body.
In 1994, an A1 series was introduced, followed in 1995 by the introduction
of the A2 series, containing many internal changes. In some cases model
numbers also changed.
Most vehicles from the initial introduction through the current production
models are still in service, so occasionally there is some confusion regarding
the model numbers.
The 1994 A1 technical data package (TDP) was based in part on previous
development work toward an M1097 "Heavy HMMWV Variant" (HHV). HHV durability
improvements that were proliferated across the vehicle variants ranged
from a new front axle assembly and front halfshafts to a new rear axle
assembly with variable rate rear springs. In addition to these and other
new HHV chassis components, A1 advances incorporated across the new production
fleet included: new front seats, improved parking brake lever with safety
release, metal hood grille, improved slave receptacle, solid state glow
plug controller, modified rifle mounts and upgraded rear half shafts.
The M966 2-litter armored mini-ambulance was eliminated that year.
Assigning a different model number with the addition of a winch was
dropped for the TOW missile carrier. Thus the M1036 model number was dropped
and the M966A1 was the only TOW missile carrier with basic armor. The
GVW was increased by 180 lbs. except for the M1097A1, which was still
at 10,000 lbs.
