6-Speed Automatic Electronic with Overdrive, 4WD, Cocoa/Dune Leather. Odometer is 3161 miles below market average! Mahogany Metallic 2016 GMC Sierra 1500 SLT Double Cab 4WD 6-Speed Automatic Electronic with Overdrive EcoTec3 5.3L V8 Reviews: * Powerful and efficient engines; improved tech interfaces for 2016; versatile and comfortable interior; superior ride quality on Denali trim. Source: Edmunds