On my smaller Hustler ZTR, it has "non serviceable" hydro motors because it's a residential model and the motors do not have drain plugs. You would have to split the motors or just use 100cc syringe and tubing to pull as much of the old oil out. It was not gear oil, so I used 15W-50 what my Gravely ZTR uses in its hydros. I measured what I pulled out and added about 30cc more back in. They do have overflow/vents on them.
There ya go, serviced a non serviceable motor, lol.
There ya go, serviced a non serviceable motor, lol.