When I fill the right Aux tank and park the 680FL with the switch on MAIN, the right Aux tank drains into the main until there is only about 10 gallons left.
If I leave the switch on AUX, then there is no drain. If I leave the switch on OFF, then there is no drain.
I'm about to check the switch, then will have to move on to the valves which are a real pain.
Any thoughts or previous encounter of similar problem?
No problems with filling and any draining from the left Aux tank into the main.