GMC Sierra 2013 Automatic Gasoline mileage: 300 KM or more 4WD GMC Sierra 2013 Double. Mileage around 400. The body is clean. It has modifications from Bullet, which are: Bullet cat-back exhaust with "Y-pipe", "off-switch", Profender shocks, King springs, muffler, Bullet, and a 40,000 BTU transmission cooler. The car is, ماشاءالله (Masha'Allah), clean and capable.