I have a 2016, 4540. The hydrolic system on mine has 2 drains. One is located just in front of the strainer, the other one is just below the power take off shaft.
When you take out the front plug, the system does not completely drain. I think it leaves about 3 gallons of fluid in the sump. This works well if you are servicing the strainer.
The dip stick is between the seat and gear shift lever and just to the right. It is under a big, about an inch, nut. This is also the fill point.