Gear oil is a lubricant designed for high-pressure machinery components, reducing friction, preventing wear and tear, and protecting against rust and corrosion. It is derived from mineral or synthetic oils and contains additives that enhance performance and extend the life of the oil and machinery it lubricates. These additives include viscosity index improvers, extreme pressure additives, anti-foaming agents, and rust and corrosion inhibitors. Gear oil is thicker than conventional motor oil and classified by viscosity ratings, with grades like SAE 75W-90 or 80W-140.