farmall m problems

Someone may offer advice on filing ring gear teeth. I never tried it but it sounds alot easier than changing ring gears. You will only need to file three or four teeth. YOu will probably notice which ones are bad.

If it is a jammed starter, you will hear a popping sound from that area when you rock the tractor backwards in fifth gear.

A weak battery can cause smoking because a low voltage condition will cause amps to rise above normal when starter calls for juice. Poor connections will do the same.

I tried that tooth filing thing. I'd try a lot to get out of splitting the tractor. (Mine's an H)
Mine wasn't jamming; it wouldn't engage at all, just grind. There were about six worn teeth at each of the two stopping points. This picture's a 'Before.'
I used a Dremel, spent hours carefully reshaping teeth. Did no good at all, far as I can see. I'm still using the hand crank to turn the engine a few degrees every time I shut down, get fresh teeth in front of the starter. That'll do until I have to split the tractor for a new clutch. Might outlast me.
Wm

When we say jammed, we mean the starter is not properly engaging the ring gear and everything gets locked up. It does not mean that the starter is seized when inspected after separation from the tractor.

I think that you count on more jams in the near future if you don't remediate the problem. Good luck.