Ecnerwal may be right. I have a 4500 with a 755 on it (the largest hoe offered). He is also dead on about the screens. My 4500 also uses the frame as a fluid storage tank and there is a drain on the lowest part of the left frame on the inside. Also, if you drain the milky fluid into 5 gallon pails and let it sit for several months the oil should seperate so you can pour it off the top. One other PITN I noticed about mine (yours may be the same) is that the return hose (to the main tank) dumps fluid right on top of the filter. When the fluid is cold and the filter pressure bypass spring kicks in the dirty fluid dumps right past the filter into the screen. My screen was always clogging up. I built a little plate on top of the filter to deflect the fluid to the sides. I also drilled a new hole in the filter rod so I could double the pressure of the bypass spring. Have never had an issue with the screen clogging up since.