Red Line heavy ShockProof 58204 gear oil is a unique lubricant containing a suspension of solid microscopic particles as an extreme pressure agent. It provides a unique solid dispersion, which cushions gear teeth to help prevent tooth breakage and allows for the use of lower viscosities. The viscosity characteristics allow the lubricant to resist throw-off and provide a film thickness similar to a 75W250 grade, while providing the same low fluid friction as an SAE 75W90. This gear oil is recommended for heavily loaded racing differentials and transmissions, off-road racing, and problem gearboxes.