Sounds like some of you may be having a different problem than what I experienced - I was ready to pull the axle/drive apart but realized my drive belt had not broken but had stretched to the point where it wasn’t getting good friction on the huge drive/clutch(?) pulley under the seat that’s attached to the main drive unit. Replacing that belt worked for me. Also, there’s a metal tang/guide toward the middle bottom of the tractor that helps keep that belt on the pulley - I recall I have to bend that to get the belt on…but then also be sure to bend it back so that the belt runs nice and clear and can’t pop out of there. You don’t want it to wear by contacting that metal - but it also has to do its job and keep the belt on the pulley when clutching and there’s slack in the belt.
Hope this helps - but for those who obviously have drive/gear/bearing issues - man I wish you the best of luck, you’re braver than I am doing a rebuild. I find I can usually locate one of these tractors used for a couple hundred bucks or less - and I use the old one(s) for parts.