It is a synthetic (polyalphaolefin) gear oil blended to SAE 75W-90 viscosity and can be used in all car and truck axle applications calling for a GL-5 gear oil. BG Ultra Guard provides thermal stability, optimum drive line efficiency, quieter operation, protection against wear, pitting and corrosion, seal compatibility and improved seal performance, improved fuel efficiency, reduced maintenance, long drain life, extended component life, application versatility.