It provides excellent oxidation resistance, maintaining viscosity and preventing the formation of harmful sludge and varnish at elevated operating temperatures. GL-4 gear oil is specifically recommended for spiral-bevel hypoid gears found in older passenger cars, light trucks, and SUVs, typically manufactured before the widespread adoption of multi-speed automatic transmissions.
GL4 Gear Oil Technical Breakdown: Understanding Viscosity, Thermal Stability, and Sulphur Phosphorous Content for Optimal Performance
Performance Benefits and Longevity Utilizing the correct GL-4 specification offers tangible benefits for vehicle operation and maintenance. The primary differentiator is the friction characteristic.
These standards define minimum requirements for viscosity, thermal stability, corrosion protection, and gear scuffing performance. Crucially, GL-4 maintains a moderate level of Sulphur Phosphorous Content (SPC), providing robust protection without exhibiting the overly aggressive friction modifier profile of GL-5, which prevents potential damage to bronze synchros in manual transmissions.
GL4 Gear Oil Technical Breakdown: Understanding Viscosity, Thermal Stability, and Sulphur Phosphorous Content for Optimal Performance
This thermal stability translates directly into extended drain intervals, reducing the frequency of maintenance and the long-term cost of ownership for compatible vehicles. Consequently, GL-5 should never be used in manual transmissions or wheel bearings, as it can lead to premature wear and failure.
More About Gl4 gear oil
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