Intermittent starting issue that is driving me to madness

[Turdle]

Check the large power feed wire connection at the starter. Grab the wire and try to wiggle it, see if that connector moves, loose. It happens.

Also, the braided conductor on the starter may be unwoven causing poor conduction. If you can, the next time you have a no start, have someone turn and hold the key while you wiggle test the braid.

My truck recently developed a intermittent no start after a trip to a body shop. I knew right away they had disconnected the battery for welding because they greased the post. I blamed this for the no start because it started right off after cleaning it.
2 days later on a dairy queen run with the missus, it did not start right off. Like it was dead, just a click. I tried again and it started.
Next day I got under there and discovered the loose starter wire. Looking at the direction of the nut's thread, and the direction of the engine torque, it is clear how the engine torque could cause it to loosen over time.

.

 

[GRNMACHINE]

Thanks Jon! I will check that out. I originally thought it was the Maxiguard hoodlock/starter kill device I had installed a few decades back. It makes 1 click like in Jason's video which is exactly what it does when the Maxiguard system is engaged. Shop that installed it is still in business and I had them check it out. Even with the sytem disconnected it still has intermittent start. Truck will turn 23 in 5 days and still has original starter.