GMC has been rolling out variants of their trucks that have been slightly enhanced for off-road driving. What started with the Canyon and Sierra 1500 now comes to the GMC 2500 platform with the 2017 Sierra HD All Terrain X.
GM Expands Silverado/Sierra Bi-Fuel CNG Availability
The bi-fuel system automatically switches to gasoline when the CNG tank is empty, or drivers can manually switch between fuel sources while driving. The 6.0L V-8 engine features hardened valves and intake/exhaust valve seats.