Gear oil is used to keep gears running smoothly. It protects the gears from wear down, corrosion, oxidation and rust. Gear oil is available in various weights. Applications differ by weight.
An oil’s use can be determined by the SAE number or grade it is assigned. Numbers of 60 and higher indicate gear oil while lower numbers indicate engine oil. This means 75W-90 and 80W-90 are both gear oil.