Multiple threads on this one.
The “fix” is dropping the tank and doing the Harpoon and/or Hutch (search either of those along with Transfer Flow) modifications. The issue is the vent tube is too far down in the tank.
41 gals is Max in the “46 gal” Transfer Flow without the vent mod and at that point it is on fumes and starting to suck air. On a diesel you do NOT want to be sucking air. Bad enough on a gasser.
Beastie 3: 2002 7.3 EB Cargo: Agile TTB, CCV Mid Top, Custom Walk Through, Lots of stuff added. BlingMyRig.com