Today, I removed the starter from the truck and performed the two tests suggested by Hotrod Lincoln. It acted exactly like it's supposed to in both tests. In the first, the solenoid pulled in and shoved the pinion gear out with a good sharp motion. In the second, the pinion gear shot out and spun like it was a brand new starter.
I took the starter apart. Here are some pictures.
Below are two shots of the fork that forces the pinion gear toward the flywheel. I don't see any problems here:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2004.jpg[/IMG]
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2005.jpg[/IMG]
This is a picture of the commutator head. I had not polished it before this picture. I see no signs of burning or any kind of damage:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2007.jpg[/IMG]
Pinion gear and associated mechanisms:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2008.jpg[/IMG]
I'm curious about the bubbly condition of the red paint or whatever it is seen in this picture. Is it supposed to look like this?:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2009.jpg[/IMG]
Here are two pictures of mud and grease that had gotten inside the case:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2010.jpg[/IMG]
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2011.jpg[/IMG]
This is the only thing that looks really suspicious to me:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2013.jpg[/IMG]
Check out the crumbled insulation below my thumb. None of the others in the case look like that. Also, there's a threadbare wire connected to it that doesn't look right:
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2014.jpg[/IMG]
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http://i7.photobucket.com/albums/y261/bohon/Starterinvestigation2015.jpg[/IMG]
According to the bench test, my starter is good. But could it be that the problem, whatever it is, only shows itself when under a load? Also, when I tested it in the truck by bypassing the ignition switch and wires, it still acted up. So either the switch and wiring are not the problem or my test was screwy, which I don't think it was. I took a ten gauge wire, touched one end to the battery and one end to the big starter terminal. Stumped on this one but will clean everything up and await advice.
Thanks.
