2000 Ford (4cyl diesel) tractor hydraulic lift problem

Please help!
I have a 2000 Ford (4cyl diesel) tractor. Hydraulic lift had been working erratically for a while but then a couple of months ago it just quit lifting altogether and I am just now getting around to trying to figure out what to do with it. I have spent several days researching this problem and after trying all of the following, I run out of things to try. Please help!
First, an issue of milky hydraulic fluid was corrected by draining & flushing with new fluid and then refilling to the fluid level test port on the right side of tractor (does not have dip stick). Removal of the plug on the hydraulic pump at first revealed very little erratically spurting fluid with tractor running so after replacing plug, I made several attempts to pressurize the system (at fluid level test port) in an unsuccessful attempt at priming the pump. (This was done while moving the lift lever up and down with engine off and also while running). Next, after replacing the test and fill plugs, I tried to pressurize the system by sending air pressure backwards to the reservoir thru the plug port on the hydraulic pump. My theory was that if the screen was blocked, this pressure would free the blockage as well as pressurize the system and in return force the fluid back up thru the pump – still no fluid at the pump (multiple times with engine on and off). After pouring several ounces of fluid into the pump (using a fill hose at the plug port) both with and without being followed with air pressure, I could hear the air going into the reservoir but again after multiple attempts with engine on and off – still no fluid at the pump, not even the original “erratically spurting fluid”. I don’t know if this has anything to do with the issue or not but I have also found that the draft control lever will not move to the upwards position that’s shown in many of the online pictures I can find. It seems to only have about ¼” movement in either direction but I am not familiar enough with this particular unit to know if that is natural or what. I would appreciate any ideas that might prevent me having to do a possibly unnecessary surgery on this thing! Thanks in advance.

Not at all familiar with that particular system, but sounds like the pump is starving for oil or sucking
air instead of oil.

A "wet sump" system has the pump intake located below the oil level, so it should self prime. Possibly a
clogged strainer could be restricting it.

A "dry sump" system has the pump located above the oil level and the pump draws oil up to the intake. An
air leak in the sump line, or a clogged strainer can cause the problem.

The milky oil could have been air bubbles, especially if it cleared up after it was let stand. Air in the
oil is a symptom of clogged strainer, low oil level, air leak in the suction line.

Might post on the Ford forum below for a more specific answer.

Steve,
Thanks very much for your assistance. I have an old friend here who used to be the shop foreman at a local tractor dealer who agrees with you about the filter. He was under the impression that I could access that screen via a 6" x 6" plate with several bolts that is on the side of the sump area near the fluid level test plug. After removing that plate (on this tractor it only has 4 bolts & is about 4" x 4") I found no way to access that screen. When I reported to him that the only thing I could see thru that opening was 2 separate lines going from the top of this area down to the bottom of the fluid sump and that I could see no way to remove them, he was at a loss. It appears to me the only way to get to a possible screen at the bottom of one of those lines would be to remove the entire top plate assembly (under the seat). I see no other way to access any type of filter or screen but if I am wrong then please advise. Thank you again very much for your assistance. ThePiddler