I have a L3400DT (2006)
No PTO or 3Point problems on mine, and I use implements that require one or both all the time. (Bush hog, box blade, boom pole, PHD)
Problems I have had that others on this forum have also run into are:
Cracked sight-glass
(New one is made from a different type of plastic, if you have the old one replace it before it goes bad, hydraulic fluid is not cheap)
Cracked hydraulic pump intake hose
(I believe the paint makes it inflexible, my replacement was not painted)
Frozen chair suspension
(Mine has never worked, if yours works, keep it oiled, may not be a problem if tractor is kept inside)
Broken fuel filter housing
(I drive my tractor in a lot of brush; I now keep a spare housing just in case, may not be a problem for some depending on the land and work being done)
Over all its minor stuff, I use my tractor hard, I am happy with its performance.