Run out of Foley Hytork Fluid for your Hurth marine transmission? Don't use "gear oil"! Hurth marine transmissions won't tolerate SAE 90 weight gear oil. This heavy, bunker oil will damage the transmission's composite clutch pack. Additionally, the tight internal clearances, assembly tolerances, and roller bearings of a Hurth marine transmission are just not designed for 90 weight oil. So, in the absence of our Foley Hytork Fluid use synthetic non-petroleum based automatic transmission fluid (i.e. ATF). We recommend Red Line Synthetic ATF because it significantly lowers heat build-up. Some of our field service vehicles have over 100,000 miles of hard driving on their automatic transmissions using synthetic fluid with no maintenance of any kind.

Please call us with any questions.  We take Hurth tech support very seriously!