I decided to pull the gas tank out of the truck this afternoon. The removal went pretty easily, except that I ended up destroying the filler grommet and I cut the rubber grommet where the gas line passes through the floor of the cab. Both of those pieces are cheap and easy to find, so I was not too upset.
I thought I was low on gas and that it would be a good time to get the gas tank cleaned and sealed. Turns out, I have a lot more gas than I thought. But it is really gunked up with rust.
Racecar Man and I tried to filter the gas out of the tank and into gas cans, but we gave up, after straining a few gallons through several layers of cloth diapers. There was so much rust that our diaper-filter would clog after just a few seconds.
I am going to price having the tank cleaned and sealed at a radiator shop. The DIY supplies seem to cost anywhere from $20 to $60. A new tank costs $200 plus shipping with a new fuel sender and float for the fuel gauge. Before I do anything with this tank or order a new one, I am going to look around a little, to see if anyone around here has a used tank in good shape.