The 2006 GMC Sierra 2500HD is available as a 2-door, 3-seat regular side. Starting at $32,675, the 2006 GMC Sierra 2500HD SL 4x4 Crew Cab Long Box is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated The top of the line 2006 GMC Sierra 2500HD Work Truck 4x2 Regular Cab, priced at $21,825, is powered by a 6.0L, 8-cylinder engine mated to a manual transmission that returns an EPA estimated