The Hummer brand began with the H1, sold from 1992 to 2006 as AM General's civilian version of the military HMMWV, widely known as the Humvee. General Motors purchased the Hummer brand in 1999 and went on to build the H2 from 2002 to 2009, along with the H3 and H3T pickup from 2005 to 2010. The brand was discontinued in 2010, and the name was later revived in the 2020s as the electric GMC Hummer EV.

Across its original run, Hummer vehicles relied on proven General Motors powertrains rather than unique engine designs. The H1 used GM 6.2-liter and 6.5-liter diesel V8 engines as well as a 5.7-liter Vortec V8, the H2 was powered by Vortec 6.0-liter and 6.2-liter V8s, and the H3 used the Atlas 3.5-liter and 3.7-liter inline-five engines, with a 5.3-liter V8 offered in the H3 Alpha.

Because these vehicles share much of their engineering with other GM trucks and SUVs of the same era, the manuals available here draw on GM-based service information for engine rebuilds, transmission and transfer case repair, and electrical system and wiring diagrams, along with torque specifications and diagnostic procedures for these GM-derived engine and drivetrain combinations.

These manuals serve DIY owners maintaining an H1, H2, or H3 at home, independent repair shops that service these GM-based platforms, and off-road enthusiasts who depend on their Hummer staying reliable. With clear coverage of engine, transfer case, and electrical systems, the manuals support confident repair and maintenance work on any Hummer model.