The hydraulic reservoir is in the transmission/rear end housing. There is no dipstick. The fill plug is a black plastic plug near the gear shifter. There is a fill level plug on the side of the rear case near where your left heel would be. there are two drain plugs on the bottom. There is a strainer on the right lower side of the rear case held in by two small bolts. Remove and clean the strainer. If it has any holes in it, replace. Since the tractor has a loader I would use oil that is rated for transmission/hydraulic or in other words, equivalent to JD 303 oil. A 5 gallon bucket is way more than enough. I think it will take somewhere around 3.5 gallons, or 12-13 liters.