GMC Sierra 2014 Used mileage: 300 KM or more GMC Sierra 2014 modified to 2018. Engine is guaranteed. The gear has a slight jerk. Chassis is guaranteed. Airbags are guaranteed. The light is on so it doesn't come out in the desert. Mileage 300,000. Additions: Magnaflow muffler "Y" pipe Volant intake filter, cost me 1800.