The regulator was worn out on my old 86 4wd. Had problems with it for year now. Just got a new regulator. Was about to put it on, and saw that the bottom piece on the window was gone, so it wasn't hooked up to the regulator at all. Does any one know where I can find this piece, and what it's called?

 

it's called the window channel

 

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I assume the tailgate window? I remember ordering mine from an online dealership. Lots of fun squeezing the piece on the window. I think I used soapy water to assist. It's been a few years since I replaced one.