when i fill front gas tank with fuel, why does the fuel gradually on 1992 Ford F-250

goes to the rear tank? The same thing happens when i fill the rear tank with gas, it goes to the front tank.

Asked by for the 1992 Ford F-250
2 answers 2 comments
SWITCHING VALVE NOT WORKING PROPERLY. MISTAKEN ABOUT WHICH TANK HAS BEEN FILLED.
I HAVE SEEN IT BEFORE. YOU WOULD HAVE TO WIND UP WITH THE SAME AMOUNT IN EACH TANK AT SOME POINT
BY JUST PUTTING GAS IN ONLY ONE. IS THAT WHAT IS HAPPENING?
switching valve not working properly
YOU ARE THE BEST I EVER SAW! I AGREE!
poss switching valve is bad