Only one engine is offered in the H3 - a 3.7-litre five-cylinder petrol engine developing 244bhp. It doesn't lack power but feels sluggish when attempting to shift the H3's considerable weight with any pace and lacks the sophistication of petrol engines in other large 4x4s from the likes of Audi or BMW. The standard gearbox is a half decent five-speed manual which is far better than the woeful four-speed auto which is optional.
It constantly hunts for gears and isn't happy unless you are steadily cruising. Force it to kick down and it merely highlights how noisy and coarse the engine is at high revs.
The Hummer looks fairly robust and crude - and that's reflected in the driving experience. Its a back to basics approach with dated rear suspension, limited cornering ability due to the chunky tyres and slack handling. The brakes aren't especially effective either so driving the Hummer is rarely a relaxing experience unless you're gently cruising along.
Compared to modern 4x4s that are more road-focussed, the H3 feels incredibly old-fashioned. The ride is poor too and the Hummer feels busy on anything but smooth surfaces. Of course where it does excel is off-road and all models come with permanent four-wheel drive, with buttons on the dashboard to lock the front and rear axles together or to engage low-ratio gears.
There's also an optional lockable rear differential which helps maximise traction in tricky off-road situations.