“From the beginning, the H1 was designed above all to be capable. Built to military specifications, the HUMVEE spin-off H1 is rugged to the core,” said Michael C. DiGiovanni, HUMMER general manager. “There isn’t another vehicle on the planet that performs like it.”

Power for any occasion
For 2004, the HUMMER H1 is powered by a 6.5L, turbo-diesel V-8 engine that delivers 205 horsepower at 3400 rpm and an impressive 440 lb.-ft. of torque at 1800 rpm. That’s 10 horsepower and 10 lb.-ft. of torque more than 2003, and meets the new federal emissions standards for 2004. The enormous torque is an important element in H1’s ability to crawl out of mud holes, up steep inclines and over rocky terrain.

H1’s powerful diesel is mated to GM’s Hydra-Matic 4L80-E electronically controlled four-speed automatic transmission. Over time, this transmission monitors the customer’s driving technique and adjusts for driving style. The New Venture Gear Model 242 transfer case enables the driver to customize the drivetrain configurations to match virtually any terrain. The transfer case adjusts manually from high gear for highway, to high-lock for slippery surfaces, to low-lock for driving off road with maximum power and torque.

No pavement? No problem!
Power is useless without control, and H1 is designed to allow the driver to go almost anywhere with confidence. H1 has a four-wheel, fully independent suspension system and variable-rate heavy-duty coil springs. The front suspension incorporates a large stabilizer bar to improve handling and reduce sway when cornering. In tandem with the wheel and tire assembly, H1’s suspension provides a comfortable ride even on the roughest terrain.

Four-wheel drive is standard on every H1 and features TorqTrac 4 technology. It automatically reduces tire spin on severe terrain or slippery surfaces by applying the brake to the spinning wheel. This allows the differential to redistribute torque to those wheels with traction.

As if that weren’t enough, H1 owners may opt for the Off-Road Adventure Package. This package is the ultimate in off-road equipment and includes front and rear Eaton ELocker locking differentials. Activated instantaneously at the push of a button, the front and rear differentials can be locked for optimum slow-speed capability in climbing over large rocks or long, steep grades.

The Off-Road Adventure Package also includes a 12,000-pound winch kit; 17-inch, 2-piece aluminum wheels with dual beadlocks; and Goodyear Wrangler MT/R tires. Goodyear GSA tires can be substituted for the MT/R tires.

Leaving the civilized world behind
Other SUVs claim the ability to take their owners off the beaten path. Few, however, can truly leave the civilized world behind. By the numbers, the H1 can traverse a 60-percent incline, a 60-percent decline and a 40-percent side slope. It can clear a 16-inch straight ground clearance obstacle and climb a 22-inch vertical step one tire at a time. The truck can also ford 30 inches of water, which is why there are drain plugs in the floorboards.

The following are just a few of the features inherent in every H1 to ensure an off-road adventure second to none:

Dimensions and design
The H1 has the unique combination of a low center of gravity yet a high, 16 inches of ground clearance—almost double that of any other 4x4. A long wheelbase (130 inches) and nearly 72-inch wide track give it the famous HUMMER stance of wheels at the far corners of the truck. The placement of the wheels provides the key to H1’s off-road prowess, an approach angle of 72 degrees and a departure angle of 37.5 with a break-over angle of 35 degrees. On the 17-inch aluminum wheels are 37-inch heavy-duty off-road tires.

Flexible body
The body is made of flexible, lightweight, corrosion-resistant aluminum. The heat-treated aluminum body panels are bonded together with a structural adhesive and riveted—just like an aircraft allowing the body of the vehicle to flex in uneven terrain. This riveted technique is expensive but the flexibility it provides is an important element of the truck’s off-road performance.

Brakes
H1’s four-channel ABS four-wheel power disc brakes are mounted inboard as a component of the axle assembly, making them less vulnerable to damage than conventional wheel-mounted components. By tucking the brakes inboard, H1s can protect the brakes from mud, sand, silt or water during off-road maneuvers.

Geared hubs
Whether on or off road, safety and control are all about traction. That’s why every H1 comes standard with one of the most useful torque delivery systems in the world: the geared hub. In actuality a mini gearbox right at the wheels, the geared hub takes incoming axle speed and further steps it down at a ratio of 1.92:1, effectively delivering twice the amount of torque to each wheel. Combined with the rest of the drivetrain, the geared hub gives the H1 a total gear reduction of 3.33:1.

CTIS
Another signature feature of the H1 is the Central Tire Inflation System (CTIS) with Runflat Tires. CTIS enables H1 owners to adjust tire pressure on the move to adapt to varying terrain. H1 off-roaders have the unique flexibility to drive on highway (32 psi) to a trail and then deflate their tires (22 psi) for maximum off-road performance without stopping the truck. Due to the hard rubber wheel inside the H1 tire, H1’s Runflat Tire System enables drivers to continue driving on a “flat” tire for up to 20 miles at 30 mph—ideal when the nearest service station is not right around the corner.

Frame and rocker panel protection
A welded steel box frame that is bolstered by five heavy-duty cross members, is strategically located on the H1 to absorb the stress of operating in severe terrain at full Gross Vehicle Weight. Additional driveline and rocker panel protection is featured on the truck to protect the vehicle underneath. The 3/16-inch thick T6 aluminum rocker panel and tubular protection help provide confidence that boulder and body damage are less of a concern off road in an H1.

Load up!
Don’t worry about packing light when taking the H1 off road. In fact, a heavy load of up to 4,000 pounds won’t sacrifice an ounce of the truck’s performance on or off road. Built to military hauling specifications, the H1 can accomplish its most extreme off-road tests fully loaded. The truck also is capable of towing over 7,000 pounds.

Turning radius
Tight corners on the trail or the occasional street U-turn are surprisingly simple with H1’s tight 26.5-foot turning radius.

Central venting
A sealed central venting system protects major drivetrain components from contamination. A 1/4-inch diameter hose connected to the vent on each component leads to a central hose connected to the air filter. This equalizes the pressure inside the gearboxes, enabling H1 to operate in up to 30 inches of water, while minimizing the threat of water, sand, silt or mud contamination.

Cooling system
Heavy-duty multiple cooling systems provide the H1 superior cooling capability for engine coolant, engine oil, transmission/transfer case fluid and power steering fluid. Maintaining fluids at the correct operating temperature increases the life of the powertrain components and allows H1 to operate under even the most extreme conditions.