Which arm? are you talking about the lift arm? or feed back rectangular metal piece?
The arm in the second picture you posted above. It has the cotter key/pin. Feedback arm.
The feed back piece returns the spool valve to neutral position or basically dumps the unused hyd fluid back to diffy housing.
if you have no resistance there then I can deduct you have no flow there at the spool.
Not having pressure at the gauge is indication of no flow ?
I have zero reading on the gauge. The needle never moves.
Does the needle on the gauge move any at all?
Previously you said you had flow at the discharge banjo fitting at the pump so I can only assume your screen is clean and not plugged up.
You also said that once you took the spring at the pressure regulator you had flow.
It has flow from the pump, to the banjo by the seat and you can see if cascading down
When you had the feed back arm pin removed and with the tractor on, did you manipulate the lift position control lever?
I did not try to move the position lever with the pin out. I can try.
If all you said was completely accurate then you would have flow to the spool valve and the spool valve is defective.
This is pretty strange. Please reply to my questions and articulate as much as what you do or see.