The 2005 GMC Sierra 2500HD belongs to the first-generation Sierra heavy-duty trucks. It's a robust pickup truck offered in numerous cab styles, including regular, extended and crew cab, with standard rear-wheel drive (RWD) and optional four-wheel drive (4WD). Depending on the trim chosen, it can be powered by one of three engines — a 6.0-liter V8 producing 300 horsepower, a 6.6-liter turbo-diesel V8 offering 310 horsepower, or a massive 8.1-liter V8 churning out 330 horsepower. All engines comes paired with a slick-shifting four-speed automatic or a heavy-duty five-speed manual transmission. Unfortunately, high-tech infotainment features were not standard fare during this era, but essentials like air conditioning and AM/FM radio come standard. Higher trims offer luxury features like leather seats and premium sound systems.