I would start by checking the starter relay first. It is in the fuse box, is often the problem and it's relitivly cheap. To remove the starter You start by collecting as many socket extentions as you can find. Unhook the battery completly, then jack up the truck take off the passenger side tire, at this point you have two choices either remove the suspention on this side of the truck or be ready for lots of fustration as you wrestle the starter out and the new one in. Unplug the starter relay wires and unbolt the main power cable from the batt. Unbolt the starter and take her out.