Ok so the hydraulics on my 45 have never been right,would not hold, always lifts or drops, so I just set a chain to stop the drop at w/e depth, was going to conquer this at a later date, mind you it's set per the funny decal for hold, no luck, after some brush hogging the other day, chains as stops in down pos, I raised it and drove back to shop, now it won't lower, I removed cylinder from rock shaft,it falls,reinstall cylinders to rockshaft, pulled plug outa the top removable valve, a lot of pressure , arms then lowered, swapped upper removable valve from parts tractor , no change, I guess it's in hydraulic valve body that bolts to tractor?? What could have happened, thanks dusty