The Sierra 2500 was the three-quarter-ton variant of the 2nd Gen GMC Sierra that debuted for the 1999 model year. These pickup trucks were available in both short or long bed versions, as well as with sleek Fleetside, fendered Stepside, or Sportside bed sides. The standard engine was a 6.0L V8, but other optional V8 engines were offered. In addition to the gasoline V8s, a diesel option also available. Regardless of the engine selected, manual or automatic transmission options were selectable, as well as rear or all wheel drive. Production of the 2nd Gen Sierra 2500 ended in 2005, when the variant was discontinued and folded into the GMC Sierra 1500HD.