If your talking about when you start to roll it up the front end dips down and jams , Then I had the same problem on my 00 mustang v6.. Im pretty sure the gt and mine would be identical. Its the glue on the window that has came off. Only way to fix this is to take the window out and reglue it <OR> buy a whole new window. The way to take out the window is stupid, You have to take rivets out just to get it out and then reinstall rivets. I took it to a shop and had them reglue mine which was like 90 bucks but a couple weeks later it came off so bought a new window for like 200bucks. Ya ford screwed over on this. The glue hardly ever works ( Then again mine's a convertible so it may be a little different). Hope this helped a little.