Originally Posted by DocBrown
Yea, tried all that. Doesn't seem to help. I also have an aversion to that being that I had a nasty incident with one of my PUPs years ago. Visions of a trailer rolling down an incline are still very vivid. :P
I would suggest a long, thin pry bar. Look in Auto Zone for something 3' long under 1/2" square. When unhitching, put the bar forward of the ball and force the coupling upwards against pushing the ball mount downwards.
The 3" of resistance end vs. 33" of effort should give enough pressure to achieve separation without risk to limbs.