Every 500 hrs drain the fluid. When it's emptied look underneath for three little bolt-heads in a triangle pattern maybe 1.5" apart. Undo them, pull out the screen filter, clean, put back exactly the same way, button up, refill with hyd/trans. There's no external filter.
Location depending on the Yanmar ...
- Located just below the p.t.o. shaft and a little forward.
- Lie under and find where the bottom of the right axle joins the main central structural body. About 7 or 8 inches forward, look for a fitting that points to the right. It's connected with those three little bolts and has a drain plug in the middle. That's it. For less mess, take the plug out first.