I have a 2010 Ford F350 with a V-10 and a mid mounted fuel tank. Just recently i began having problems putting fuel in the gas tank as it would fill the neck and shut off the nozzle. I have dropped the tank and made sure all lines and vents are clear. Replaced the evap canister and valve due to dirt contamination and then everything was fine. Two weeks later with no rhyme or reason the fuel is again backing up in the filler neck. The only thing i can think of is that with a full tank the fuel is hitting the check valves at the tank vents causing them to close and one or both are sticking in that position. There is no replacement available for the valves just replace the whole tank is what Ford is telling me. Sorry at 600 bucks i want to be damn sure this is the problem. Any help would be greatly appreciated. Thanks.