Make sure you checknthe connections on the starter itself, make sure that there is not a bunch of corrosion on the connector, (and its not green looking), If your happy with that,mthen try using jumper cables off your truckmconnected to the battery. That will help deliver extra cranking amps, even with some bad and or corroded cables, and at least you'll have something to compare, to the process your going through now. You also, can take the plugs out, then crank the engine several revolutions, with no compression. This will also make it easier for the starter to turn the engine over several times, and you shouldnt have any problems. If you do.. then you need to start focusing onnyour starter or bendix.