Lucas Extreme-Duty Marine Automatic Transmission Fluid ATF 946ml 10651Lucas Extreme Duty Marine ATF is a blend of specific synthetic base oils and a special Lucas additive package designed to create a high friction fluid that allows shifting clutches in the transmission to lock up and engage quickly. A faster shift means less clutch slippage, therefore, less heat and wear in the transmission. Fortified with special synthetic additives that coat moving parts to protect against rust and moisture during storage.