Sounds like the balls are shot in your coupling. I had one like that, it was possible to push the window down and pull it up, all you have to do is overcome friction between the window and the felt and overcome the springs. You may be able to pull the rear panel and pull the glass down a few inches from the inside. That would allow you to do the rest of the work from the outside which is so much more pleasant. Otherwise, youd just need to pull the motor from inside the truck.
Cleaning the coupling out, replacing the balls and repacking it all is probably a 10 minute job once you have the motor out. Sorry for your luck :(
Another confusing thing- your tailgate key switch is supposed to work all the time. The switch in the dash is only supposed to work with the key on. Took me a solid week to figure that out..
These 11mm ball bearings are what I used
https://www.amazon.com/gp/aw/d/B07YKN93SC?psc=1&ref=ppx_pop_mob_b_asin_title
1984 Bronco, mild built 300-6, Np435, 3.55 gears, 8.8 rear with Eaton TrueTrac, D44 TTB front, 31" tires, MSD ignition, Offy C, EFI manifolds, Holley 390, No AC, 3G alternator, front receiver
1988 F250 "One Piece at a Time" - 460 ZF5 4x4 work truck project under construction