About three years ago I decided to buy a garden tractor and somehow ended up with not one but three Bolens "projects", in various states of disrepair: a 1220, a G12, and an H16. Along with these I got three mower decks (all with seized spindle bearings, of course), a couple of tillers, and an assortment of Brinley cultivating tools.
The G12 and H16 weren't running when I bought them, but the 1220 was (more or less). I drove it up the ramps into my pickup, down the ramps and into a shed at home. There it's sat for the last three years!
This summer I decided it was high time I did something with these wrecks, and since the 1220 was a known runner I've started with it. I did some work on the engine, cleaned out the fuel system, did some necessary rewiring, and it's running fine.
The problem is the transmission: it runs in reverse just fine, but none of the forward gears are working! Yes, the driveshaft is spinning (remember, it backs up nicely.) What's odd is that it worked just fine before I parked it.
I've done a lot of engine work (diesel and gas, small and large) but have never taken apart a transmission. Given the symptoms, what problem should I be looking for?