you probably should have started your very own new post about your issue.. but lets take a look.
first. need to know if you have an 8n or 9n.
there are minor differences to the hyd covers and pumnps.. and will make a difference on R&R advice.
are there 2 levers by the right side of the seat.. 1 3" and the other longer like 7" in a quadrant?
is it a 3spd + reverse with a brake on each side and clutch on left... or a 4spd + r with 2 brakes on left, and clutch on right.
now. with pto engaged.. you say it will not lift with lever up.. but will lift with no implement.
pull right side inspection cover where the dipstick is, and look in with pto running and lever up to lift and implement on.
if you see a spray of oil or a steady stream from somewhere.. post back.
prime leak spots are at the front top and lower bottom where the top cover and bottom pump plate bolt to the center section.. there is a pressure tunbe running top to botton int he front right side of the casting.
the tube can perforate.. or leak from the gasket top or bottom.
the hyd lift piston rings can be shot and leak from the cyl mouth... can leak fro mthe gasket holding pressure under the cyl, can leak from pump chamber covers and gaskets.. can leak from a faulty relief valve.
can also be bad pump chambers not pumping... etc.. etc...