The Type of Fluid to use in a TR-1 Autopilot

The TR-1 Gold autopilot system requires hydraulic fluid. The only type of hydraulic fluid Garmin recommends, is called BioSOY. Other products, even in an emergency, are not recommended as they can damage the system or cause it to work improperly.

BioSOY is no longer available through Garmin, but can be found online or local retailers.  If there is not a supplier of BioSoy, ISO32 type fluid may be used.