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. At this time, the convertible/soft top and the station wagon versions are the only ones available in the mass market. The two door and four door pickup versions are only available in fleet livery.
Five engine types and three automatic transmission types can be found in Hummer H1s. The common engine/transmission combinations are:- 6.2 L Detroit Diesel V8/GM TH400/3L80 3-speed
- 6.5 L Detroit Diesel V8/GM 4L80-E 4-speed
- 5.7 L Vortec 5700 gasoline V8 TBI/GM 4L80-E 4-speed
- 6.5 L turbo Detroit Diesel V8/GM 4L80-E 4-speed
- 6.6 L Duramax LLY turbo Diesel/Allison 1000 5-speed (model year 2006)