The 2003 GMC Sierra 3500 is available as a 2-door, 3-seat regular side. Starting at $31,400, the 2003 GMC Sierra 3500 Base 4x2 Crew Cab is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated The top of the line 2003 GMC Sierra 3500 SLT 4x4 Crew Cab, priced at $36,550, is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated