I am working on a 560 for a customer, who swapped out a pump from a 460. I've been chasing a bad howl/growl noise. I swapped out power steering pumps as well. I noticed the lower pto gear is chipped up in spots. I also noticed the pump gear isn't meshing too deep into the drive gear. I split the tractor to replace the large pto gear, (its a 51 tooth ). are the pumps the same from 460 to 560? I also looked into all the valving, and I bypassed the hyd system and ran the hose back into the rear end to bypass any valve issues, no change in noise. I changed the fluid and filter as well.... I am guessing the noise is from the gear not meshing correctly but not sure if anyone ran into this before........