Jubilee remote hydraulic valve problem

I bought a remote hydraulic valve about a year ago. The valve comes in 2 pieces, a top and bottom. The top is 3 plates sandwiched together which holds the valve assembly, and the bottom is one piece which mounts directly to the top of the tractor. I have been trying to get it to work correctly since I got the valve. I intended to use the valve for a hydraulic top link like I have on my 861. So I purchased a new hydraulic top link and associated hoses etc. When I mount the valve on the tractor, with no load on the top link or 3 point lift, all works well. Lift goes up and down and top link goes in and out with no leaks. When I mount my brush hog on the 3 pt., the top link, unloaded, still goes in and out but the lift will not lift. The lift tries to go up and the arms get tight but it will not lift and oil leaks out from between top and bottom pieces of the valve. Not between the valve and the top of the tractor but between the top and bottom pieces of the valve. I tried to clean the 2 surfaces and replace the o rings but I am not able to seal the leak.
The leak does not look bad, the oil is not squirting out 6 ft away or anything like that, it just seems to flow between the plates and down the side of the tractor. So that obviously needs to be fixed. But my question is if that leak is enough to prevent the lift from lifting the brush hog. I don't want to go thru the trouble of getting that fixed only to find that the valve has other more serious problems.
I haven't opened the valve completely yet, as there are several plates involved and the bolts holding them together are capped with plugs.
Any opinions or suggestions are welcome
Thanks
Alan

I don't know that valve but it sounds like an original Jubilee remote valve like I used to have but never used, a stacked plate type. I believe one poster on here said they are pretty rare.