Uneven fuel level in tanks.

[TRUCK365]

Hi guys, I am back after a reassessment of the situation based on everyone's input. Turns out that instead of a splitter valve, this 2020 Cascadia has a simple T (either that, or I did not find the splitter valve). We took apart the return line and T going to both tanks. Nothing came out. No obstructions. We took out the vents and vent tubes, blew some air in them also. Nothing came out. Put everything back together and sent it out with the driver for a short test run. Going on three days without a problem so far. Driver is able to fuel up and tanks equalize just fine. It seems that whatever we messed with did the trick. A huge thank you to everyone that contributed.