Gear oil is a specialized, high-viscosity lubricant engineered to protect manual transmissions, transfer cases, and differentials in automobiles and heavy equipment.It is specifically designed to handle extreme pressure (EP) conditions, high shock loads, and severe sliding friction between gear teeth that regular engine oil cannot manage.
Key aspects of gear oil include:
High-Pressure Protection (EP Additives): Unlike motor oil, gear oil contains sulfur-phosphorus EP additives that form a protective film, preventing metal-to-metal contact, gear scoring, and pitting under heavy torque.
Viscosity: It is much thicker than engine oil (e.g., 75W-90 or 80W-90 vs. 5W-30), which cushions gears, reduces noise, and ensures a durable, protective layer.
Corrosion Protection: It contains rust and corrosion inhibitors designed to protect internal components from moisture, especially non-ferrous metals like copper or brass found in synchronizers.
Heat Dissipation: It absorbs and transfers heat away from gear sets, ensuring stable operating temperatures to prevent oil breakdown.