under the seat of tractor is the hydraulic reservoir. fill it to the line on the dipstick.
back of tractor below fuel tank.
Looking at the back of the tractor. On the left hand side above the PTO
The back of tractor -you should see a round plug about the size of a silver dollar -just twist ant it should pull out ! Youll see hydraulic fluid there !
The only hydraulic fluid which is typically in a road tractor is the power steering fluid, and you simply fill that to the fill line on the reservoir. If it's been fitted with a PTO, that's an aftermarket system, and that, as well as the hydraulic tank, depends on who the aftermarket supplier is.
The hydraulic fill is a pipe plug just to the left of the shifting lever as you sit on the tractor.
On the slightly newer CK20S, if you are sitting in the tractor seat, the hydraulic fluid fill will be near your right hand as you reach down below the seat. It has a red cap on it that says "oil". This is NOT the engine oil, but rather the hydraulic oil.
You gotta take out the fill plug. Check the fill plug to see if any metal shavings are on it, the fluid level should be to the bottom of the fill plug. If you're taking an oil sample, a fluid transfer pump or siphon hose should do.
Should be on the mid to upper rear of the tractor. It should be the cap about 2-3" diameter directly above the PTO.
There is a square head plug on the left side just in front of the clutch pedal. When you remove it there will be a dipstick attached to it.
There is a small round window on the transmission that can be seen just behind the clutch pedal on the left side of the tractor. The hydraulic fluid must be filled so the oil level is between the two lines etched on the window. It takes about 8 gallons of hydraulic fluid for a drain and fill. The fill hole is under the rubber plug on the raised portion of the seat area between the driver's knees. There are four drain plugs.
Remove the fill plug and top it off with hydraulic oil.