Let’s call them window sliders

Not sure if it's related but I just put new window felts on my '72 Dodge pickup, it was REALLY hard to roll the window up and down at first so I cleaned the window and then liberally applied Rain-X water repellant and they're much easier to move now, doesn't feel like I'll break off the window crank now lol.

Also if anyone else does these make sure the door glass is clean first, mine had a bunch of built-up dust which must have had sand in it because now my window has some vertical scratches :(