48 one ton,

How interesting. I thought all the cabs had fuel fill holes and in cab tanks regardless of GVW. My 4400 has the in-cab tank.

It sure would be a first step to drop the tank and inspect the sending unit. Sometimes a cleaning and a little more tension on the wiper will make them work again.

That would also allow you to see it up close and determine if the one listed in the catalogs might fit.

Stuart