The Hummer H1 Alpha’s development began in 2002, after manufacturer AM General was granted permission to use General Motors’ V-8 diesel engine in the vehicle. The “Alpha” version of the H1 was introduced to combat lacklustre sales of the standard truck, with customers complaining it was underpowered relative to its petrol alternative. General Motors engineers proposed fitting the 6.6-litre Duramax turbo diesel—usually deployed in the GMT560 medium duty trucks—in the H1. Extensive modifications were made to ensure this powerplant would fit on the chassis of the Hummer, ringing 23 changes for components on the engine, while the body was lifted two inches to accommodate clearance of the taller diesel unit. The chassis was reinforced with high-strength steel to cope with the additional demands of the engine.

The Duramax diesel engine of the H1 Alpha was further equipped with a cooled exhaust gas recirculation and an internal engine cooler. Due to limited space under the bonnet, the fan system was modified and driven by a special gearbox connected directly to the crankshaft. The fuel and filtration systems were revised, and the H1 Alpha was equipped with main and auxiliary fuel tanks. The cooling system was altered to enable easy cold-starting from temperature as low as minus-32 degrees Celsius.

This H1 Alpha was manufactured in October 2005, leaving the factory in Mishawaka, Indiana, finished in Diamond Black with a black front crash bar, black light bar, electric winch, Hummer Central Tire Inflation System (CTIS), and forged aluminium dual beadlock wheels. Inside, the interior was fitted with black and white piped leather seats, rubber floor mats, cream headliner, and a leather-covered, three-spoke steering wheel.

The H1 Alpha was equipped with instrumentation and amenities including temperature gauges for the gearbox oil, engine oil, coolant, as well as instrumentation for tyre pressures and fuel levels. This example features heated seats, factory-fitted radio with supplied Nokia mobile phone, power windows, and air conditioning. The driver can inflate or deflate all four Goodyear Wrangler tyres using the CTIS controlled through a gauge and switches in the cabin.

This example was last serviced at 30,524 miles on 21 September 2020. The odometer shows fewer than 31,640 miles at the time of cataloguing.