I have a newly acquired 410 backhoe an 80s machine. I had a few bad O rings on the pressure control valve mounted on the side of the tranny. I fixed the leaks to find fluid pouring out of the bottom mounting bolt for the valve. I thought the two o rings behind the block maybe bad replaced those with jd o rings. Still leaks from thw bottom bolt. Someone had added a copper washer to the bolt which obviously shouldnt be there. Has anyone had this issue? Maybe the control valve is internally cracked? Or that bolt hole has pressure behind it?
Heres the valve
I guess a crack is possible? Maybe valve tolerances have been lost and pressure making it to bolt hole? Do you have access to the valve tear down picture/parts list?