GMC Sierra 2021 Used mileage: 250 KM Sierra for sale, model 2021 SLE. Mileage: 250,000 km. Body is original, guaranteed, and the engine is original, guaranteed. Additions: - 40,000 BTU transmission cooler by Oxid. - Bilstein shocks. - Sports thermostat. A set of four tires recently installed a week ago, brand new. All additions were installed 5 months ago, new. Inspection and registration are new, ready for transfer.