Unless anyone has a good reason to go NAPA, I figure I will go with the suggested Motorcraft after all the troubles I have had.
This truck has a 4.6L V8. I think this is the NAPA part. Either way, if those here feel Motorcraft reman is the best bet after all my hassle, that is how I plan to go.
https://www.napaonline.com/en/p/NRO4N9278?impressionRank=1
Yes that is the oneā¦
I would not be afraid of either oneā¦ 
BTW, what was the name of Fordās rebuilt parts supplier few years ago?. I seem to recall āCharlieā as the first name. Their engines were world class quality and reasonably priced.
Iām guessing pretty much the same as everyone above, all of the replacement starters were āiffyā from the get-go. Suggest to either purchase new oem from a Ford dealership, or if they donāt have new ones, a rebuilt from a Ford dealership. Ford brand name reputation is very valuable to them, so a Ford dealership isnāt likely to sell iffy-quality rebuilt starters. My Corolla tends to go through starters every 3-4 years, and its first replacement starter was rebuilt, Toyota-branded, from a Toyota dealership. Worked fine, reliable starts for 10 years. Later installed some parts-store rebuilds, 3 of which were no good out of the box. Current unit is Denso-branded rebuilt from parts store, obtained from same parts store after initial parts store non-branded unit wouldnāt spin even once, Denso rebuild has been working good.
Less likely , but its possible you have an electrical problem in the truckās wiring. Easy enough to rule that out. If voltage at starter motor is at least 10.5 volts probing between terminal(s) and starter case with key in āstartā, not a truckās wiring problem.
Once you finally get a good quality starter motor, suggest to keep it, donāt turn it in for core rebate when it eventually fails. Just have it repaired by a local auto-electric shop.
Well, I figured out the problem!
The root cause of all these strange no-start issues with this truck has been found. What happened is that the solenoid wire to the starter had corrosion through SEVERAL FEET of the wire! Anyway, I had a junk trolling motor in my current scrap pile. The copper wire from it was the tinned marine variety and heavier than the factory wire so I cut away sections of the factory wire until I could see bright clean copper. It was like pure black and brittle inside the wiring for at least the first foot, then another foot and a half or more was quite questionable. Then I made a nice section of replacement wire from the junk trolling motor and soldered it in place. The new starter is hitting with gusto and fires the engine right upā¦ but there was a catch.
I had installed a new starter switch under the dash. The first time I started it with the new starter and after my wiring repair, the truck started but seemed quite sluggish. I figured maybe it had been sitting and with all my tests, having the key in the on position, etc. that the battery might be a tad drained. I let it run 15 minutes and shut it off. Then there was NOTHING. No clicks, not anythingā¦ I was like, āWhat did I do now?ā
Anyway, I decided to test the firewall solenoid. I removed the solenoid signal wire and jumped it with a screwdriver to the hot side. The solenoid hit, the starter engaged with gusto, and the truck started. So I jumpered the start pins on the clutch safety interlock to bypass the switch. Nothing changed. I checked Fuse 23 to see if it was blown. I found some suggestions online indicating that this was a common culprit but it was fine.
The old starter switch was right there so I decided to put it back in since my dash is still all taken apart. The starter engaged with gusto and all was well. So I put the new one right back in, making sure everything was connected and aligned properly. There was still no start or signs of ANYTHING. I put the old one back and it fired right up!
Anyway, I am just glad that I finally got to the bottom of this strange and annoying problem. I donāt think I am going to even mess with getting another starter switch, just return the bad one. Obviously that wasnāt the root cause of why my starters or mainly the solenoids were burning out. Taking apart the part of the dash isnāt a huge deal if I do ever need another switch. Also, in a pinch, jumping the firewall solenoid makes a great workaround.
The truck does have like 300,000 miles or more (It has been stuck at 279,000 ever since I bought it). I figure the old starter switch may be about done for but that the truck might have something major fail in the meantime so why even bother with a new switch if the old one seems just fine and wasnāt part of the issue?
Apparently it wasnāt! A simple voltage drop test while operating (or trying to) the starter would have found the cable corrosion issue. But glad you got it fixed now.
I think it is one of those no-load vs/ load tests. OF course I was finding that the main hot could take the amps and the volts but wasnāt really concerned about the amps on the signal wire. Apparently things looked up for this wire, especially after anytime I was under the truck messing with the wiring. Having it disconnected and all was definitely a no load test and the wiring would be bent in a way that is different from how it was when connected to the starter.
I figured it HAD to be something like this and there was no way one could go through starters more often than you needed to fill the tank, even with a parts store brand, especially the most expensive/best they have to offer.
I found a suggestion online about starting issues on Fords of this era. Apparently the wires were prone to corrosion.
That is the deal with these intermittent issues. They can be hard to find and electrical gremlins are the worst. The wire looked just fine on the outside as well but once cut, a different picture emerged. Either way I am glad to have gotten to the bottom of this mess.