if its not essential to remove it from your truck stal dont touch, reason is mate i can most likely gaurentee that youll shear of most of the bolts that hold on the tank, probably find the filler pipe very coroded and will want replacing, also the rubber pipes will split but worst problem youll come across is you will probably make holes in the tank, where the tank hangs is a poxy little mud trap and causes tank corossion, but in itself is a very easy job to remove theres only a few bolts holding it to the chassis on the rails, most pipes you can get to wiggle of as you let it down easy but DONT let the tank drop as ut kinks the main filler, to aid getting to this open the fuel filler cap, pull back rubber and undo the screws these will most likely want drilling out due to rust, but the rest of the job is straight forward, on top of the tank is the two sender wires these just pull of, remember to take them off before letting the tank right to the ground, good thing is the tank isnt heavy, any other questions just ask.

Is there a way of fitting a drain bung without any welding?
contemporary radiators