Fuel filler hose

[V8VAN]

The piece between that connects filler and the tank?

If so, you can do it without removing the tank. I had to do it on the WB van I had. Not too hard, but a PITA.

[Kingsandman]

Should be able to loosen clamps And slide rubber pipe up filler tube and off fuel tank lip then pull it down off filler tube ,getting the rubber piece off is fairly easy ,putting the new piece back in is a lot harder working in a small gap but can be done without pulling the tank out.