Hi there, I have a 1967 John Deere 5020 that just had all its hyd oil flushed, rebuilt main hyd pump and cooler replaced with one that has a check valve up by the radiator. The other day i used it for harrowing and all of a sudden the tractor chattered as it had trouble lifting and dropping the harrows. The steering is beginning to act like there is air in the system too. Also now when i try the pto, it does nothing. Out of gear the shaft spins a little bit but while in gear, it turns really slow and theres no power it seems to it. Is it the gear pump? Can one fail so fast? I thought they gradually wear over time, not right away. Or do i need to try to adjust the pto engagement itself? Im at a standstill on this one and would appreciate any help.