from the OP:
I have now hitched and unhitched successfully with the new Reese. It's model 30852, and is different from any other hitch that I have used. I like it.
To unhitch, I pull the arm out to 9 o'clock, but that does not open the jaws. You then rotate the arm clockwise to 10 o'clock. That opens the jaws. While still hitched with the kingpin pressing on the hitch, the arm will remain at 10 o'clock and the jaws remain open. When you pull away from the kingpin the arm returns to 9 o'clock and the jaws close.
When I was playing with the arm before trying to hitch up, there was no kingpin pressure on the hitch, the arm would not remain at 10 0'clock and the jaws would not remain open. That's what got me confused.
Also, the jaws are supposed to be closed when hitching. They are designed to open up as the kingpin moves into the hitch. That's different from what I'm used to.
This hitch is what Reese sent me to replace the Ford factory-installed hitch that I damaged by backing too hard into the trailer. I reported that in a earlier post, hoping to warm people that backing too hard can ruin a 5-th wheel hitch.
