I got a rototiller at the dump. The motor is fine, but it wouldn't
shift gears. The "transmission" was a bitch to get apart, but I did it
and found rust, as I expected. I'm undecided between pitching it and
rehabbing it.

Even with the rust removed, the gears will be very rough and wear
quickly, but:
- it would get very little use (maybe an hour or two per year)
- the transmission runs at fairly low speed (900 rpm max input, down to
maybe 50 rpm on the wheels)
- it only handles 5 hp

My feeling is that under these conditions the transmission would last a
long time and perform normally, if noisily.

Finally, I like to rehab machines, but I don't like to waste my time.

A pic of one of the gears after HCl de-rusting and bead blasting (the
teeth are about 1/4" wide):
http://home.comcast.net/~bobengelhardt/RustedGear.jpg

Waddaya think?

Bob