"from soundguy" One thought, blown cyl packing.
Leave lift hose in, remove dump hose, pressurize lift, see if oil blows out dump.
thinking it out load of soundguy last sentence above....
fully extend the hyd cylinders for the bucket.
--nearest to the rod portion of the hyd cyinders. disconnect that hose (remove hose / quick connect)
--try to extend the hyd cylinders more (pressure relief most likely will kick in). hold it there for a couple seconds.
--if a seal is bad, and trying to still fully extend cylinders, leakage should get by the seals and blow out of the hose.
--reconnect everything...
--you will need to fully extend and fully contract the bucket cylinders a few times, to clear them of majority of all the air. then just normal use of FEL will help clear out any little bit of air in the hyd cylinders. until majorty if not all the air is out. the bucket / FEL arms may have some bounce to them.
repeat above but opposite ends of cylinder checking...
--fully contract the cylinders.
--disconnect hose furthest away from the (rod end of the hyd cylinders) (no quick connect on hose)
--try and contract the cylinders. if a seal is bad in the hyd cylinders, you should get oil coming out. ((no oil = good to go most likely))
--reconnect everything....
--you will need to fully extend and fully contract the bucket cylinders a few times, to clear them of majority of all the air. then just normal use of FEL will help clear out any little bit of air in the hyd cylinders. until majority if not all the air is out. the bucket / FEL arms may have some bounce to them.
goal of above, each rod inside the hyd cylinder has some "seals" and many times there is a large nut, that holds them in place. some times this nut has came loose on folks. and it might be letting seals do there job. other times the seals just go bad. some times the rod gets bent and the seals end getting damaged as well. and the goal of the test. is to see if seals hold when tractor is on, and using the joystick to actually put a force on things to test the seals out.
if you had a pressure gauge and a quick connect hose for it. this would be easier and less messy to check. a dealer more likely already has this.