Yeah thanks Henry for the diagram. Kat your link helped me find the picture I needed thank you!
Truck cut off going 70mph cruise. Will turn over but no start. No leaking fuel. Pulled oil filler tube and took a quick picture. Rolled it into the shop, midnight Saturday. I'll find out later what happened.
It honestly looks like the nut is still there but it has pushed itself further up on the shaft. Then I think, "This can't be possible because the tapered area on the shaft prevents this from happening." Maybe the shaft itself came out of the pump? Threads are obviously ruined. If the nut is in fact not on the pump, then what is the hex head shape "nut appearing" part behind the threads? I looked at the diagram and in this picture I attached and I can't find what would be hex shaped if the nut was not on there. If the nut did fall off.....my motor should be locked up in the gears? It turns over just fine.