I know it has to do with the dual tanks since it has four lines going in and two out and it's leaking what's it called though?

 

If those wires are going to it, I would say fuel pump.. although that doesn't make too much sense considering we have them in our tanks.

If those wires aren't going to it, maybe it's a filter?

 

looks like a filter for me

 

Not the filter or pump because I've never known of then to have more than 3 pumps.

 

maybe its a small reserve so the engine doesnt die when you change tanks or its a selector valve

 

I've only said it like 1000 times, it's the dual function reservoir. And yes trucks with those have pumps in the tank and another pump in front of that.

 

It has another name I figured out that was Fuel Selector Valve

 

I call it what Ford calls it.

 

Every time I searched for it with the name you called it by it shows up nothing lol

 

Semantics.... like Sean said its a DFR. Some call it a fuel selector valve. It has a hydro-mechanical valve assembly in the upper half that changes its state when low pressure fuel is applied to one side or the other. It changed the valving for return fuel as well. Also it has a small reservoir in the lower section to keep fuel supply during switching operations. It is the source of many problems with our fuel systems which I suspect is why Ford deleted it in later years and went to a simpler system with check slaves and in tank high pressure pumps.