I am getting ready for the cutting season. I've had my used Scag Turf Tiger Zero Turn mower for 2 yrs now & never replaced the hydro fluid. I bought new oil & filter, but where do you drain it at?? How often should the hydro oil be changed?? I have an Exmark I recently bought used also-how do I drain that as well?? By the way, does anyone know where I can buy a cheap Exmark seat? Do you have any idea how many quarts of hydro oil it would take to refill the Scag & Exmark? What's a good engine oil grade to use on these machines? Can you tell I didn't get owner's manuals for either?! Any help would be appreciated!