If you have a floor jack I've found it easier to raise the bed rather than drop the tank. Just remove the three bolts on the drivers side bed and loosen the pass side, disconnect the fill and vent hoses, watch for any wires that might go tight when you jack the drivers side bed up. With this method it doesn't matter how much fuel is in the tank. This is also the method that most dealers use. Make sure to wedge a 2x4 in-between the bed and frame while you are working in there, it would make one heck of a mouse trap.