The Sierra K2500 was the three quarter-ton, all wheel drive variant of the 1st Gen GMC Sierra that debuted for the 1988 model year. These pickup trucks were available in both short or long bed versions, with the sleek Wideside truck bed. The standard engine was a 4.3L V6, but three optional V8 engines were offered: 5.0L, 5.7L, and 7.4L. In addition to the gasoline V8s, a diesel option also available. Regardless of the engine selected, manual or automatic transmission options were selectable. Production of the 1st Gen Sierra K2500 ended in 2000, when it was replaced by the 2nd Gen GMC Sierra 2500.