Hi Pferg. It sounds like the window jaw mechanism has come loose. Many have had this problem. You will need to do some exploratory surgery to be sure. Have you ever removed the interior door panel? If not, don't fret. It is not difficult, it just takes some time. I am hoping somewhere in our archives is a step-by-step on how this is done. I can probably describe it since I've done it a zillion times but I may forget a step or two...
In the mean time, don't force anything -- the glass will shatter and you will have made things a lot worse!
James
63 230SL