OK so from your input and your input on other threads too (go internet!) it seems like with my PTO I've learned:
1. PTO is possibly an Independent PTO due to the engage/disengage lever being between the shift levers. A few threads lead me to believe this while a few others leave me in doubt. Just a curiosity.
2. PTO should engage/disengage via center up/down lever. It does not seem to do this. Perhaps I should put a bush hog on it as next step to see how it performs under load.
3. I have no left foot PTO disengage. Only a diff lock lever, to my understanding.
4. It sounds like perhaps the PTO brake or clutch assembly is failing, which I can test for pressure somehow around the base of the shifters. I see two green bolts, two black bolts more towards the steering column. I would like to test this if I can figure out how. Between myself and my neighbor we have the tools to accomplish, I'm handy just not a mechanic and not much tractor experience.
Photo of what I see attached. I'd love to be able to test and determine the problem without hauling back to shop. FYI the shop didn't say a word except "it has a live PTO" but the number one requirement for me to take it off the lot was to be able to go home and start bush hogging. I guess I can, but kinda irritated.