Due to other spring duties that must be done, this job has been postponed many times. Found no metal chunks in oil. Starter was full of water in bendix area, armature turns free but bendix doesn't. Don't understand how it even engaged the flywheel. Still need to inspect flywheel. Solenoid had been clicking a couple of times before starting tractor, may have been the bendix causing this. Some condensation around brush area also. After finding water, didn't try to bench test. My buddy who worked for a DC motor repair co. said he would rebuild it for me so he has it now. He took it apart in my garage and took it home with him in a box. He's slower than I am so it could be a week or two. He said solenoid didn't look like rebuildable type, but he would free the bendix and check for grounding, clean armature etc. As far as he could see at that time, all else was ok inside starter. Brushes, bendix drive gear, bearings ok. His plan is to just clean it up and put back together, then give bench test. May have to replace solenoid.
Will give you his analysis of the squeal and stall. All just opinions. Due to a worn alternator belt, (I didn't think it was that bad) alternator may have squealed after battery had set all winter and was low on voltage. Bendix may have stuck on flywheel and caused the squeal. He has no idea on the stall. He doesn't know diesels either and was looking around asking me questions that I couldn't answer either. He asked if the hydraulic pump had ever given trouble. No. He said that he thought his ideas were far out in left field, but I told him I was open to all suggestions. Still am I guess. All still pointing to internal.
Actually, over the 20+ years I've owned this tractor, All I've had to do to it is change fluids and filters, replaced original battery and replaced one front inner tube. Also did a temporary/permanent fix on a rear valve stem I broke off on a stump.
I may be doing wrong, but my plan is to get the starter back on, cross my fingers and fire it up. I do want to try to turn it by hand in proper rotation again 1st. Sorry to make such long posts, but maybe they will be of help to someone if I do find out something. So far, I don't think I've contributed anything useful at all. There are probably good diesel mechanics that are reading my posts for entertainment. haha
Anyway, thanks everybody and look for the final update. Hopefully positive.