I am the person who suggested he move or repost his issue to the Yanmar part if TBN.
Thank you all for doing what you do! You have responded with lots of helpful information!
THANKS!
It seems we need more info from the OP.
What was posted from my view could be a control valve for a loader or for rear remotes or even a low mounted snow blade.
Personally while not a hydraulic guru either, I have done some repairs on these systems. Assuming this was not an OEM part but an aftermarket add on (such as a FEL) even if installed by the dealer at purchase, I would probably replace the control valve with a new unit as he has indicated the JD shop wanted to do. Excessive wear in close tolerance areas seem in my experience to have short term effectiveness. Others may have different experiences and different recommendations.