Star Fire Full Synthetic 75W90 Gear Lubricant is a multi-purpose lubricant designed for service in automotive and heavy duty applications. Star Fire Full Synthetic 75W90 Gear Lubricant is formulated with synthetic base stocks and a sulfur-phosphorus extreme pressure additive package with friction modifier, which provides excellent thermal and oxidative stability, as well as anti-foam, anti-rust and anti-corrosion protection and have excellent load carrying capabilities.