There is a filter built into the oil tank. Reusing old reservoir when servicing gearbox system will introduce expired fluid and contaminants back into the system, affecting Solenoids, Accumulator, and any other component in the system.
We recommended changing the oil tank when doing any hydraulic fluid service to F1 System.
Note: This tank is for a later version of the F1 system. If you have an earlier generation of the oil tank, you will need to also change to a new screw cap.