This is a hardy tractor and has the Select-O-Matic transmission. Supposedly when this transmission come out there was a lot of problems, but Ford worked with people to iron out the problems.
When I've worked the tractor hard, sometimes it won't go into certain gears. Not everyone works on this kind of transmission and if you decide to have someone else do work on this transmission, you may have a hard time finding one.
PTO engage/disengage cable can present problems. It is not a very solid engage/disengage system and sometimes it will not do what choice you make. Currently my PTO is stuck in engage position.