Stuck Window Regulator

['68OrangeSunshine]

The Drivers side Window Regulator on my '71 GMC Jimmy is stuck at about 1 inch up. Won't roll up. Won't roll down.
And, as I recall, you can't disassemble it with out the window being cranked all the way up.
For now, overnight, I have a sheet of foamcore show card, ~5/16'' thick, cut out from tracing the other window, wedged and taped on, to keep out small critters, dust, wind and light rain. [Two legged critters I'll just have to shoot.]
Gears on the crank drive sound/feel like they're stripped. Handle rotates thru 30 -45* between contact. Window will go up 1/4'' or down 1/4'' but otherwise stuck.
I replaced this regulator 11 years ago, but the K/5 doors have no upper frame to protect them like on my C/10, so the insides get wet and this rusts.
Can't run the truck into town, since I can't lock it up.