EP 90 Gear Oil is the lubricant made for transmissions, transfer cases, and differentials in automobiles, trucks and other machinery. It is a high viscosity lubricant. This lubricant is used on gears to reduce noise. Gear lubricants can be straight mineral oil and extreme pressure lubricants. To prevent the rust inside the gearbox and wear between moving gears, gear oil is used so that it enhances the performance of the gearbox and help them to run smoothly.