If you looked at the link above you will understand better what I am describing here. Turned out to be a 4-hour job -- I'm pretty slow with a wrench. I removed the left footboard and hydraulic pipe section under the footboard. Then I pulled the round cover on the left side of the trans housing. The wire-mesh intake filter attached to the inside of the round cover was covered with a slimy coat of material that looked like vaseline. When I cleaned up and reassembled, the hydraulics were like new again.
I caught about a gallon of hydraulic fluid that drained out the round port and a pint that came out the pipe leading to the spin-on hydraulic filter, so be ready with pans. I probably should have replaced all the hydraulic fluid, but I topped it off with about a gallon of fresh, and I'll see how it goes.
Good luck with yours, Johnny.