When I got the tractor this spring, I did the engine and had the fuel tank off, so I figured that I would take that opportunity to put a seal kit into the pump. Got the seal kit and took the pump apart. The last piston I took out was badly scarred and wouldn't come out of the housing. Needless to say, by the time I got it out, the housing was done. I have no idea for how long it's been like that, but it's a safe bet that some particles went through the system. I worked on most of the tractor, but didn't get into the detail with the rockshaft or the tranny since they were working fine at the time. I drained all the oil off the tractor including the power front wheel drive since I put new bushing and seals into it as well.

I don't know but I got a gut feeling it's a stuck valve or something.