The Sierra K3500 was the one-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 5.7L V8, but an optional 7.4L V8 was offered. In addition to these engines a diesel option also available, which varied from naturally aspirated to turbocharged depending on year. Regardless of the engine selected, manual or automatic transmission options were selectable. Production of the 1st Gen Sierra K3500 ended in 2000, when it was replaced by the 2nd Gen GMC Sierra 3500.