I know what this is....
Their is a track the glass sits on that can be adjusted..... Look at the window when you put it down then look real close when it goes up.... The window will shift. The more the shift, the slower it goes. I don't know how to tighten the track but any Autoglass place does know how to do it. Just go to one and tell them you need the window centered and tightened on the track.
It's cheap to do it too... Like $20 or something. I did it on my old car back in 1994. I forget the price but it fixed my problem....
Most of you where in Elementary school in 1994. LOL!