Red Line's Heavy ShockProof Gear Oil is a unique lubricant containing a suspension of solid microscopic particles as an extreme pressure agent, unique solid dispersion which cushions gear teeth to help prevent tooth breakage and allows the use of lower viscosities. Recommended for heavily-loaded racing differentials and transmissions, Off-road racing and problem gearboxes. 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.