6-Speed Automatic, Ebony Cloth. Recent Arrival! Stealth Gray Metallic 2013 GMC Sierra 1500 SLE RWD 6-Speed Automatic Vortec 5.3L V8 SFI VVT Flex FuelOdometer is 41566 miles below market average!Reviews:* Smooth, quiet ride; comfortable seats; powerful V8 options. Source: Edmunds* If your towing needs run in the 7,000-10,000 pound range, a compact pickup isnt going to cut it; the full-size 2013 GMC Sierra, on the other hand, will. Models range from a basic Work Truck to the frugal 23-mpg Sierra Hybrid to the luxurious Denali. Source: KBB.com