I loosened the bolts, marked the slip clutch plates and mowed heavy pasture grass with it in increments.
In Hawaii a high-protein, fast growing grass was introduced for cattle. It can grow to ten feet. The botanical name is Megathyrsus maximus, which tells it all even if you don’t speak Latin. Sounds like a Marvel Comic hero.
Back to the point.
During the test, the mower frequently slowed and I then lifted it until it resumed full PTO-rated RPM and again slowly increased the mowing load. The tractor engine stayed steady at 2600 RPM during the mower-slow events. After several cycles of what seemed likely to be a properly functioning slip clutch, I shut it down and found the slip clutch plates were still lined up, much to my surprise. The mower slip clutch was still stuck.
My neighbor, a veteran of this forum, thought it possible that my JD 2032R tractor’s PTO had its own slip clutch that was absorbing the energy, which turned out to be the case.
I will now disassemble the mower slip clutch to see if it’s serviceable or if I need to replace the plates.
I think I dodged a bullet by being saved from potential damage by the PTO slip clutch.