How do you replace fuel pump and sending unit 1988 GMC truck?

drop the gas tank, un hook the the filler neck hoses, unplug the wires from the top of the tank, beat the lock off he top of the sending unit (on the top of the tank) then pull it out, its all one assembly, then you can take the pump off, or relpace the entire unit. its a pain in the arse, ive had to do it 6 times on my 88 gmc truck. ohh, yeah, be careful and dont drop the tank on your head, ive done it. dropped tank=pain