JD 60 Steering

Scott, you probably are either getting fluid by-pass in the pump or more than likely by-pass in the steering vanes inside the front steering unit. ~You can remove the nose grille sheetmetal & remove the front steering line from the steering valve at the top & reconnect at the bottom & place the open end in a can or bottle then with the engine at fast idle turn the steering wheel to the right & see how much oil is by-passing the steering vanes [if over 1/2 quart in 1/2 minute you have too much internal leakage in the vanes].
~You might try removing the cap on the flow control valve [see picture, yellow arrow] & turning the valve in a turn or two as that will allow more oil to flow to the steering system [if available],,,,internal leakage could make that ineffective]
~I am not recommending you do this, but I have a 70 that had the same problem as you are having & as a temporary repair I installed 20W50 weight oil in the steering system until I could get around to installing new vanes in the steering unit. That was 5 years ago & I still haven't got around to installing new vanes, it is still working good so it hasn't been a priority.....