70 GTX door window rocks

Hi, The driver and passenger door windows on my 1970 Plymouth GTX tilt back to front, sort of like a rocking chair. If you push at the top of the window at the back the window will move down only in the back (sort of rocking front to back)and come partially out of the front track. Any idea what is broke or needing adjustment?

Thank you,
Joe

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/1657963/door-glass-glides.html#Post1657963

Thanks for the quick response. I wonder if just the clips need to be replaced? I see the felt in the track.

Joe