The 2013 Sierra 1500 is available in several trim packages, including Work Truck, SL (crew cab and extended cab), XFE, SLE and SLT, in 2WD and 4WD configurations (XFE is 2WD only). The range of body styles and configurations includes: three cab styles -- regular, extended and crew cab -- and three cargo box lengths: 5 feet 8 inches (short), 6 feet 6 inches (standard) and 8 feet (long).
GMC Sierra 2500HD and 3500HD trucks work hard -- and do it with unmistakable GMC style. There are 10 Sierra 2500HD models, eight 3500HD models and six Sierra Denali HD models -- including regular cab, extended cab and crew cab body styles offered in 2WD and 4WD, as well as single- and dual-rear-wheel configurations. All are available with either a standard gas V-8 or the powerful Duramax 6.6L turbo-diesel.
Click the attached link below to view the complete factory technical specifications of the the 2013 GMC Sierra and Sierra HD in .pdf format