Does the hydraulic pump have a large 3/4" whitworth (now I'm showing my age!) what looks like a blank plug looking from beneath, if it has, remove and the flow divider/priority valve is there over the years experience all it will need a check of the o rings and a clean up put everything back as you found it, number of turns on the threads etc, reassemble and test.
With oil overflowing check the scoop mounted on top of the bell housing above the torque converter loosen the two bolts beneath the cover plate push across till it stops then back a touch, I have had a few of these pick up scoops break off but invariably transmission oil is every where. Hope this helps good luck