My 2500 Yanmar became very slow lifting a 4.5 ' disc. Decided to check filter screen. Oil came out very dark amd filled with metal particles. Screen was not as clogged as I have seen, but, pretty bad. Drained all oil and removed and cleaned screen. Replaced oil with same volume as I removed (+-) used universal fluid from TSC. 3 point will not raise nor will loader, oil on dipstick shows air bubbles. I closed all cylinders on loader but now I don't remember if I lowered the 3 pt. Anyway any input is needed and appreciated. Thanks. Dan