Hi Dwight
I have quickly read most of this thread, and if it has already been mentioned/diagnosed please disregard. I have had similar experiences with heavy trucks (Class 8) not cranking well when hot, and diagnosing them can be a bit tricky. A couple things that I would check:
1- Voltage drop on starting circuit - do a control test on both + and - circuits when engine is cold, and then the same when the engine is hot. Even though the cables are new and sealed, I have seen dozens of cables in my career that have been green and rotted 6 inches back from the terminal, and if that is the case, heat may expand the damaged area and limit the contact within the wire.
2- Amp Draw on starter - Again do a control test (cold) and compare to a hot engine test, if your amp draw is significantly higher I would be looking at internal starter issue's.
Like the others have said, back to the basics, and just because its a new part doesn't always mean its a good part!
I'm sure everyone involved would like to see the outcome, so please let us know how you do.
PS: the picture you posted is very focused on the fuel gauge, Where you just showing what the oil pressure gauge looks like, or trying to show how high it is reading?
Good Luck
Jeremy
