The 2010 GMC Sierra 1500 is available as a 2-door, 3-seat regular side. Starting at $33,715, the 2010 GMC Sierra 1500 SL 4x4 Crew Cab is powered by a 4.8L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 13-mpg in the city and 18-mpg on the highway. The top of the line 2010GMCSierra 1500AWD Crew Cab , priced at $ 46,435 , is powered by a 6.2L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 19-mpg on the highway.