Originally released in the civilian market in 1992, the Hummer H1 owed its birth to the popularity of photos from Operation Desert Storm and the enthusiastic campaign from actor Arnold Schwarzenegger, who personally owns several variants of Hummer vehicles. GM announced that 2006 would be the last model year for the Hummer H1, with production winding down in June 2006 due to a new emission law for diesel engine vehicles, which took effect in 2007.
The Hummer H1 has three common variants: a convertible-like soft top, a four-door hard top pickup truck and a Wagon body version. Other less known variants include a two-door pickup truck and a four-door slantback. The convertible/soft top and the station wagon versions were the last ones available in the mass market. The two door and four door pickup versions are only available in fleet livery.
Currently, five engine types and three automatic transmission types can be found in Hummer H1s. The common engine/automatic transmission combinations are:
- 6.2 L GM Diesel V8/GM TH400/3L80 3-speed
- 6.5 L GM Diesel V8/GM 4L80-E 4-speed
- 5.7 L Vortec 5700 gasoline V8 TBI/GM 4L80-E 4-speed
- 6.5 L turbo GM Diesel V8/GM 4L80-E 4-speed
- 6.6 L turbo Duramax LLY V8 turbo Diesel/Allison 1000 5-speed (model year 2006)
The Hummer H1 shares some common driveline parts with its HMMWV brethren. Items like brakes, axles, frame and major body panels (hood, tailgate and quarter panels) are identical between the HMMWV and the Hummer H1. All Hummer H1s and HMMWVs come off the same assembly line, and then civilian H1s get painted and finished in a separate building across the parking lot.
Hummer H1s are unique in the way they handle off road, and in their interior arrangement. Passenger and highway comfort are sacrificed for maximum mobility compared to civilian SUVs, with features much more radical than the original Jeep, though they do share a similarly cut simple grille opening. They are inherently very stable, thanks to their wide stance. They also can ford 30 inches (76 cm) of water, climb a 22-inch (56 cm) step, have a stock ground clearance of 16 inches (41 cm). This high clearance is made possible by tucking driveline components inside a channel in the central space between the left and right seats. They have high approach/departure angles of 72/37.5 degrees. Most H1s are equipped with a Central Tire Inflation System (CTIS), which enables the driver to increase or decrease the tire air pressure at will- since lower tire pressures are more suited for off road, and higher tire pressures are desirable on-road.
Hummer H1s have many unusual features. They use inboard brakes. They have portal gears, allowing the drivetrain‘s half shafts to be up high for greater clearance. The radiator is up high, sloping back over the engine on a forward hinged hood. The air intake is mounted high, enabling fording waist-level water. Rather than using simple runflat tires, magnesium-aluminum alloy or rubber inserts are an optional feature for runflat ability. Chemical warfare resistant paint is available only on the military version.
2006 Hummer H1 Alpha
The “Alpha” was an extensively re-engineered H1 that was equipped with GM‘s Duramax Diesel and 5-speed Allison transmission. The previous version of the H1 with the 6.5L “Optimizer” turbo-diesel engine suffered from sluggish sales; lack of power was one of the reasons for customer resistance. In 2002, AM General CEO Jim Armour took the idea of repowering the H1 to Bob Lutz and the GM Luxury Vehicle committee. GM soon approved the use of their Duramax/Allison powertrain for the H1. This would support the continuation of the H1 as the grandparent of the Hummer portfolio; it would also allow AM General to give the truck a much needed dose of updating in terms of power, torque, refinement and the ability to meet 2004 heavy duty EPA emissions requirements.
The update program commenced in late 2002 with production launch slated to be fall of 2004. The engineering team chose the engine variant out of the GMT560 truck (the C4500) because it packaged better into the H1 engine bay; however, 23 engine component changes were required and the team had to do a 2.0 in (51 mm) body lift to accommodate the taller engine and its turbo housing (a prior 0.5 in (13 mm) lift had been done for MY96 to accommodate the turbo on the 6.5L engine). The GMT560 engine calibration was used with minimal modification; engine output was 300 hp (220 kW) and 520 lb·ft (705 N·m) of torque. Due to the Duramax engine being equipped with cooled exhaust gas recirculation and an internal engine oil cooler, the team had to deal with a 40 percent heat rejection increase to engine coolant. However, they were unable to increase the size of the cooling pack between the air-lift brackets that protrude from the hood. This meant dramatically re-engineering the fan system by putting the fan directly under the coolpack and driving it through a special gearbox directly off the crankshaft damper pulley. Several other cooling system modifications were required to assist with cold starting from −30 °F (−34.4 °C).
Other major modifications included the use of special high-strength steel in the chassis frame, a more powerful steering gear; quieter axle differentials, redesign of the geared hubs to use quieter helical gears, new induction, exhaust and electrical power systems; and re-engineering of the fuel supply and filtration system.
Off road the much higher torque of the engine, combined with a lower gearing ratio (about 44.5 to 1 in low lock), made the truck much more powerful. The Duramax engine delivered more torque at lower engine speeds than the 6.5L, so the team actually had to calibrate the torque management to protect certain driveline parts. This new torque profile coupled with centralized tire inflation and AM General’s new interior resulted in the complete re-engineering of everything except the carryover body made of aluminum beams and panels.
Production launch was early in 2005, and continued until production ceased in mid-2006. All vehicles built during this time are classified as model year 2006 (10th digit in VIN is a 6.)
The program was cancelled May 12, 2006 because GM decided to withdraw technical and financial support for future engineering and recertification.
In the original 1992 production run, the price of the basic open-top was $40,500 while a fully loaded wagon with all options was $54,700.
In 2006, the suggested retail price was $129,399.00 for the open-top; the wagon was $140,796.00, H1 Alpha was priced at $150,975.00.
The Hummer brand
On June 2, 2009, General Motors attempted a sale of its Hummer brand to a Chinese company, Tengzhong, as part of its bankruptcy settlement. GM stated at the time that it hoped the sale would save about 3,000 jobs in the US, after sales of the brand suffered despite its military image because of its low fuel economy.
On February 24, 2010, General Motors announced that the company was shutting down its Hummer brand due to Tengzhong withdrawing its bid. Tengzhong stated that the bid was withdrawn due to a failure to get approval from the Chinese government.