Conclusion:
I took off the negative wire at the block, and cleaned it with a wire brush and sandpaper.....there was some corrosion there. I also took the small bolts out of the battery terminal clamp, pulled out the stranded copper wires, and wire brushed and sanded all of that area....also a bit of corrosion going on.
Truck started right up. I drove her for 10 minutes and came back, turne the engine off.......then tried to start. Another no-go....just barely turning over.....errrr-----err---er.
The load test, the cranking test, and cell-to-cell volt tests showed that the battery was still fairly good. I even had the battery tested at the Auto store, and they said it just needed a charge. So, not sure why it had plenty of cranking power when cold, and almost none when warm.
I put a new battery in today, and gave her a test drive. Came back, turned the engine off, and tried to start.......
SUCCESS! I waited 1 min, 5 min, 10 min, and 30 minutes......started with a roar each time.
So, it was the battery. Maybe something inside went goofy whenever it got a brisk charge from the alternator, but it recovred when it cooled off? Also, the Volt Reg. had been charging a bit too high and boiling the battery over the years, and it was half a quart low in electrolyte when I checked it a few weeks ago. So maybe running low of electrolyte caused some damage internally?
Thanks for all the tips.
