At this point, open the pipe plug on the odd shaped option cover under the seat. If you have oil there and no 3pt, then there are a few possibilities.
1, stuck unloaded valve
2, bad backpressure valve (associated with acorn nut on right side center section )
3, gets tricky from here.. Could be holed piston, bad relief, massive oil leak on the valve block on the cyl, blown out gasket especially.
we did take that plug out and ran motor but no fluid came out ---even tried the blow in the dip stick hole to see if fluid would come out --nothing--if fluid is coming out of the pipe plug on top of pump that means my pump is working,-- correct, the system seamed to have 90 weight fluid in it and I read where the seals leak thru and it is alright to run hydraulic fluid in all three units to avoid any problems--is there any videos on working on the unload valve or back pressure valve system