Rear window problem

I had found a REALLY old post dealing with this issue, but the pics are broken and the PN’s are no longer any good! The proble is that, I can only assume, once apon a time, there was some sort of plastic wheel that rode inside the track of the rear window. These guides have long ago disapeared! I need help finding these and suggestions on how best to get the window out without braking it. Some pictures would be nice to.