Lucas HD Primary Chaincase Oil is a blend of easy-flowing base oils and a Lucas additive package designed to carry away more heat from the clutch and friction plates. This assures a longer, more trouble-free clutch life. Expect smooth clutch action, less slippage, longer chain and sprocket life and a much longer oil life. Cools and quiets. Designed for heavy-duty high performance situations. Meets or exceeds all O.E.M. requirements. Note: Primary Chaincase Oil is a coolant for the clutch, not a lubricant.