Prepare your truck to be Ready for the Road Ahead™, with the Valvoline All Terrain SAE 15W-40 Heavy Duty Diesel Engine Oil 1-Gallon that provides maximum engine protection. This replacement formula naturally resists oil breakdowns and defends against oxidation thanks to its mix of quality base elements. Engineered to seal microscopic spaces in the motor and keep engines in prime condition by reducing wear while improving fuel economy. FleetPride is your First Click in Heavy Duty®.