gear oil
Quick Summary
Gear oil is a type of lubricating oil used to reduce friction and wear between metal surfaces in gears. In some cases, extreme pressures can cause metal surfaces to seize, so special additives are used. These additives, often sulfur compounds, create a protective film that prevents direct metal-to-metal contact.1
The viscosity, or flow rate, of gear oil is a key property. The Society of Automotive Engineers (SAE) assigns numbers to indicate viscosity. For transmission and axle lubricants, these numbers range from 75 to 250, with lower numbers indicating a more readily flowing oil. The suffix "W" signifies suitability for winter use, with oils tested at low temperatures, while others are tested at higher temperatures. Multigrade oils, like 10W-30, use additives to maintain performance across a range of temperatures.23
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