OK problem just sarted. Truck has been starting fine. Other day I hit the key and the starter spins but doesn't turn over the engine. tried a few times. Pulled the starter (which is oil soaked from bad gaskets above) and took it to NAPA to have tested. works ok there. teeth are a little buggered up but not bad. Reinstall and I bar over the engine thinking maybe a bad spot on flywheel. Starts right up! works fine for a couple days, does the same thing. bar it over and still nothing. So I'm thinking the bendix isnt indexing everytime? thoughts?

 

If you're sure the starter is spinning (at the necessary speed) and not turning over the engine, it has to be the starter drive (bendix) or a bad spot in the ring gear. I would first inspect the ring gear all the way around and rule it out before replacing the starter drive.