Need ideas

I've had this washer since it was new 22 years ago, it has been a very good appliance. It doesn't have all those unneeded options, it just washes clothes. A few weeks ago I started a load and walked away, when I came back I had found that it didn't start agitating, and the belt was smoking. I thought that because the belt was 22 years old, that it may have stretched and would not spin the pulley. I bought a new belt, but they only come in a set of 2 for $23. Put the new one on, and it worked for a week or two, then froze up again and smoked that belt, thinking that I may have not removed all the slack when I installed it,I bought another set. A week went by and i caught it not agitating when it started, so I quickly stopped the machine and removed the front cover, then rotated the transmission by hand, then started the machine and it worked fine. It worked for about 5-10 times normally,then got stuck again and would not agitate on its own, unless i played with the transmission to get it unstuck. So I thought it may need a bearing being so old, replaced the bearing and the seal. To my dismay it works most of the time, but can't trust it, can't keep buying belts, once they get a burn in them. So now I think it must be the transmissions I take the cover off the trans and all the gears look like brand new, can't see anything wrong. Now I am stumped and need some experienced advice on what to do next,I am a good DIY,but lack repair experience on appliances. Any advice? Model LAT8035AAE