I've got an M8540 and the hydraulic fluid dipstick is located just above and to the right of the PTO shaft output in the back. The hydraulic fluid fill port is above and to the left of the PTO shaft. I'm using Kubota SUDT fluid and it's not easy to see it on the dipstick. Also, you need to make sure that the tractor is fairly level (not on a slope) when checking the fluid. Hope this helps.