1975 Used Manual Gasoline mileage: 21 KM In the name of God, the Most Gracious, the Most Merciful. 1975 GMC Sierra. Pickup. Mileage: Only 21,000 kilometers, actual mileage (confirmed in report). Engine size: 350. From old Civil Defense sales. Repainted entirely a while ago for the color. Registration not renewed and not inspected. For sale by auction. Please consider calling times.