Monthly Military: The High Mobility Multi-purpose Wheeled Vehicle


Few military vehicles have the ubiquity on the modern stage of the High Mobility Multi-purpose Wheeled Vehicle (HMMWV). Commonly referred to as the Humvee, more than a quarter million of these “jack of all trades” light tactical vehicles have been built since they went into production in 1984, seeing service across the world in varying roles in different conflicts and peace-keeping missions.

Toward the end of the 1970s, the U.S. Army had begun to search for a vehicle that could supplant both the M151 quarter-ton jeep and M561 Gama Goat, replacing the roles of multiple vehicles with one solution. After trying a few different options, including the Lamborghini-designed Cheetah (which would later be developed into the civilian Lamborghini LM002 truck), in 1979 the Army drafted a set of specifics and requirements for the light tactical vehicle they wanted to have produced, which would replace the ¼-ton to 1 ¼-ton vehicles in service at the time.

Throughout the years the Humvee has been used in a variety of different roles, both combat and support related. This example under the care of Those Military Guys in Rancho Cucamonga, California, was outfitted for cargo hauling duty.

The recipe called for a vehicle that could provide solid performance on or off-road while bolstering occupant protection, along with the ability to carry a sizable payload. It also needed to have a diesel power plant, as the Army sought to use the fuel throughout their tactical vehicle fleet, and needed to be outfitted with an automatic transmission.

The new vehicle’s dynamic capabilities would also have to far outreach those of the ones it would replace. The Army’s other requirements included the ability to climb a 60 percent incline and traverse a 40 percent slope and ford through five feet of water with onboard electronics that would remain waterproof through 2.5 feet of water as well.

Sixty-One Enter, Three Stay For The Finals

As you might imagine, securing the contract to build this new tactical vehicle would be a massive windfall for whatever company managed to land it. But of the 61 companies that expressed interest in the project, only three would actually yield prototypes: Chrysler, Teledyne Continental, and American Motors under their AM General subsidiary.


In simplest terms, the concept around the Humvee was essentially “a Jeep on steroids”, according to AM General. In truth it proved to be much more than that, offering both on and off-road prowess that went for beyond the Jeep’s while also providing substantial hauling capability as well.

The three companies were tasked with creating eleven HMMWV prototypes – five for general utility duty and six as weapons carriers. The prototype mules were put through rigorous testing in various types of harsh conditions and cover more than half a million miles in the Army’s development trials in varying terrain, which saw the vehicles in Arctic winter conditions, extreme high-temperature deserts, mountainous terrain and other challenging environments.

In 1981, AM General was officially awarded the prototype contract, with subsequent development and testing taking place the following year. In early 1983, the company was given the contract for the initial batch of 2,334 finalized HMMWVs and a total production of 55,000 units over a five-year period, a project valued at well over a billion dollars.

Initial Spec, Combat Debut

While capability was obviously high on the list of priorities for this new light tactical vehicle, it also needed to be relatively easy to operate to ensure that it would require minimal training hours to get drivers acclimated to it. To that end, the original M998 developed by AM General was motivated by a 380ci diesel V8 engine mated to a three-speed automatic transmission, which sent the grunt to all four corners through self-locking differentials.

M998 Humvees were initially powered by a naturally aspirated 6.2-liter diesel V8 producing 190 horsepower and 380 pound-feet of torque. After the conflict in Somalia in 1993, engineers developed a number of improvements for the Humvee, resulting in the M1114. That armored version of the Humvee has been in limited production ever since and is powered by a turbocharged, 6.5-liter diesel V8.

Ground clearance of 16 inches was also a requirement for the new vehicle, so portal-style axles were used, which attach to the near the top rather than the center of the wheel, to allow the driveshafts to be raised higher into the chassis.

In similar fashion, the brake discs are not mounted directly on the wheels, as you’d find on typical automobiles, but rather on the outside of the differentials.


Sixteen inches of ground clearance was part of the military’s requirement for the HMMWV. To help achieve this, the brakes are mounted inboard, attached to the differentials rather than next to the wheels like a conventional automobile. The Humvee uses a four-wheel double-wishbone suspension design.

Although optimized for off-road use and weighing in at over 5,000 pounds, the Humvee could cruise comfortably at highway speeds and reach a top speed of 70 mph.

Hummer Heads to Suburban America

While the Humvee would see its first stint in a combat zone during the U.S. invasion of Panama in 1989, it was the Iraqi invasion of Kuwait and the U.S. military’s subsequent involvement which brought the new Humvee into the collective consciousness through media reports in newspapers and TV.

The sight of its wide, low, imposing presence, coupled with its proven heavy-duty capability caught the attention of well-heeled civilians. Arnold Schwarzenegger was among those who expressed interest in a civilian version of the Humvee, and in 1992, AM General brought the vehicle to market under the Hummer name.


Early versions of the Hummer H1 sold to consumers weren’t dramatically different from the vehicles the company was producing for the military. While that meant no shortage of capability, it was also a dramatically different driving experience from what most civilians were used to – particularly for those who could afford to add such a truck to their roster of vehicles.

While it satisfied the brawny, purposeful look that these buyers were interested, the original Hummer’s military origins were a far cry from typical road-going SUVs, lacking the refinement, ride quality and creature comforts that the folks who could afford AM General’s offering had come to expect.

In 1999, AM General sold the rights to the Hummer name to General Motors, who initially would oversee the marketing and distribution of the vehicle while AM General continued to produce the vehicle itself. Meanwhile, GM developed their own Hummer model, the H2.

While the H2 shared much of the squared-off look of the H1, the underpinnings were much more conventional. In contrast to the H1, the H2 was underpinned by modified versions of the GM 2500-Series at the front end and the 1500-Series in the rear and was initially powered by a 6.0-liter V8 making 316 hp.


While it retained some of the H1’s aesthetic, commonality between the H2 and AM General’s Hummer pretty much ended there. Underneath the sheet metal, the Hummer H2 was essentially a GM full-sized truck. Nevertheless, the H2 saw moderate sales success for its first few years on the market. But the financial downturn of 2008, coupled with rising gas prices, would spell the end of Hummer brand under GM’s tenure in 2009. Image: Hummer

With a curb weight of more than 6400 pounds, the H2 took nearly 11 seconds to get from zero to sixty miles per hour, and its off-road capability was considerably reduced in comparison to AM General’s H1. Despite this, the H2 was initially well received, but its production would ultimately be relegated to just eight years when General Motors was forced to sell off the Hummer brand during their bankruptcy restructuring.

A Changing Battlefield

Meanwhile, the Humvee was facing challenges of its own out on the battlefield. 1993’s Battle of Mogadishu in Somalia showed the vehicle’s vulnerability in urban combat scenarios, as the vehicle was never designed to offer significant protection against small arms fire.

These limitations became more obvious during the Iraq War, when new threats from close-quarters guerrilla warfare and improvised explosive devices became a serious issue. In response, the military’s engineers quickly retrofitted additional armor to some of the Humvees in their fleet, but this in turn added a significant amount of weight to the vehicle, adversely affecting both performance and reliability.


After a heated battle for the contract between Lockheed Martin and Oshkosh was finally put to bed earlier this year, the initial order of 657 Joint Light Tactical Vehicles was placed in March. Its design takes into account many of the new challenges facing today’s military, and features like jam-resistant doors are incorporated into its design to address the changing combat environment. Image: Wiki Commons

While the Humvee has become a staple for military vehicular transport for the Allied forces, seeing numerous revisions, modifications, and improvements throughout the years, the limitations of the design have necessitated the development of a successor that incorporates both recent advances in technology as well as the changing scope of requirements needed by the military.

As such, the initial effort to replace the Humvee with its eventual successor, Oshkosh Defense’s Joint Tactical Light Vehicle (JLTV) is now underway, a project awarded to the company in the summer of 2015. The JLTVs will be powered by the tried-and-true Duramax 6.6-liter engine, with performance and fuel economy enhancements engineered by Banks Power. However, the Humvee still remains in production to this day and will continue its various roles within the military for the foreseeable future.

About the author

Bradley Iger

Lover of noisy cars, noisy music, and noisy bulldogs, Brad can often be found flogging something expensive along the twisting tarmac of the Angeles Forest.
Read My Articles

Enlist in the Diesel Army newsletter.

Receive the latest newsletter with the content you love from Diesel Army, directly to your inbox, absolutely FREE!

Free WordPress Themes

We will safeguard your e-mail and only send content you request.

Diesel Army


We'll send you the most exciting Diesel articles, news, truck features, and videos every week.

Diesel Army


We will safeguard your e-mail and only send content you request.

Diesel Army

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

Off road, Jeeps, 4x4s
Engine Tech
Drag Racing

Diesel Army

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • ORX Off road, Jeeps, 4x4s
  • EngineLabs Engine Tech
  • Dragzine Drag Racing

Diesel Army


Thank you for your subscription.

Thank you for your subscription.

Diesel Army

Thank you for your subscription.

Thank you for your subscription.