6-Speed Automatic Electronic with Overdrive, 4WD, Jet Black Cloth. White 2014 GMC Sierra 1500 SLE 4D Crew Cab 4WD 6-Speed Automatic Electronic with Overdrive EcoTec3 5.3L V8 Flex Fuel Reviews: * New, more fuel-efficient engines; improved interior; quiet highway ride. Source: Edmunds * The 2014 Sierraâs innovative powertrains and handsome aesthetics should appeal to longtime GMC fans and tempt buyers new to the brand. In just one of many mine is bigger battles in the half-ton truck market, the 2014 Sierraâs 12,000-pound max tow rating is expected to be king â at least for now. Source: KBB.com
