When we replaced the gears I guess the parts man said the "new" ones were of better quality.  How much faith I put in that I don't know.  Like I said, that was 8 years and a lot of acres of mowing and spraying ago.

Per the original post we were the third owners.  We recently found out the original landscaper traded it off because his guys kept treating it like a live PTO.  It was then "repaired" and sent off to sale to the neighbor farmer.  He retired and we bought it with no known issues (he cut grass with it).  I think the repair they did was simply replace the driven gear set as the original PTO shaft looked like it hadn't been removed guaging by the paint on the  output shaft seal.  So I highly doubt it was repaired correctly.

Anyways, they are a yard tractor not a bulldozer/skidloader so I think if you treat them as such you will get a long life out of them.  We did have to put a glow plug relay in it recently as that's the other known issue with them.

FWIW, I picked up a Farmall 55 (newer series) and in my humble opinion the DX class are built heavier.  I wanted a cab for blowing snow, spraying grapes and mowing.  So the DX is going to get stuck setting up augers and cutting grass now.  In many ways the 55 is nicer but it has SCR (emmisions), electronic everything, and it seems everything is pretty much built lighter (front end, loader, etc).