'65 straight 350 trouble

[ChrisMis]

I’m the owner of a JD 350 crawler dozer. I bought it 7 years ago for $6500 and it has done a great many things for me since. The biggest plus for me was having a super winch on the back to skid logs off my land. I have a house now from them and I couldn’t have done it without this machine. So, needless to say, I’m a tad attached.
This last winter, after having some work done on it in the summer, it got stuck out of gear. I’m from NH and it was cold so I thought something may have frozen up, maybe linkage or something. I tented it were it stood and heated for quite awhile with a good sized heater to no avail. I didn’t have a lot of time to deal with it so I let it sit till warmer weather. Well, my 3 and 5 year old boys were on it one spring day and they were giving it the usual “product testing” and they got it in gear again! I’m using it still from there fix.
Well, winter is coming again and I’m wondering what I should do. This dozer does our driveway for us but it’s got to be able to shift. Any ideas out there of what may have been the problem? Lots of water somewhere that it freezing? Linkage, or I guess fork issues? Is any of this doable by me? I know I said I had it worked on but that was a wield job that I didn’t feel confident on. I’ve done any other work myself.
All help appreciated.

[CELSESSER]

Pull the dipstick on the transmission. If it looks like grade B Maple Syrup then it's good, if it looks like you pulled it out of a milkshake then you have water in there. Don't remember what the shift linkage looks like on a 350, there may be a spot in the linkage that could pool water that might lock it up when it froze.
Did the trany spin when it was stuck in neutral?

[digitup]

I take it that it was the 4 speed that was the problem and it is just shift collars that can be the problem watch those things they can hit 2nd and 3rd at the same time if they get bad .The problem can be in the forks or the collars selectors .watch for loose slide shaft parts or lock bolts loose.Or worse these parts in the bottom of the transmission .If you feel like putting someone on the job that knows about such things the better .See if you can find a tractor repair shop or mobile tractor repair man to do this it may be best as this a bit sticky as jobs go .Ask neighboring farmers who they would use don't even think of taking it to Deere 350s have been out of their vocabulary's for two decades.Digitup.