Gear oils are classified by the American Petroleum Institute using GL ratings. For example, most modern mechanical gearboxes require a GL-4 oil, rear differentials equire a GL-5 oils etc. Check the oil against the vehicle manufacturer's specification proir tu purcgase.
Fully synthetic Maxima gear oils have a greater resistance to shear breakdown than mineral oils.
Most common API classification are:
- API GL-3. Oils for moderate conditions. Contain up to 2.7% anti-wear additives. Designed for lubricating bevel and other gears of low-to-medium loaded transmissions. Not recommended for hypoid gears.
- API GL-4. Oils for light to heavy conditions. Contain up to 4.0% effective anti-scuffing additives. Designed for bevel and hypoid gears and axle units. These oils are standard for mechanical gearboxes. GL-4 oils may also be used in many limited-slip differentials.
- API GL-5. Oils for severe conditions. Contain up to 6.5% effective anti-scuffing additives. Typical application of GL-5 oils are for hypoid gears and non limited-slip differentials. They arealso recommended as universal oils to higher loade mechanical transmissions.