Had the same issue with my 02 and here is what you will find. On both sides of the glass there are two plastic panels that snap in to cover the track. I had the inner plastic piece on the drivers side fall off and slid back on top of the headliner. When the roof got about halfway back, it stopped and heard the grinding. It is hard to get a good look inside to find the piece. Take off the molding strip on the back side of the headliner, just snaps off. Gently pull the headliner tabs down and look up inside with a light. If you cant see the piece causing the jamb, slowly open the sunroof until you hear the crunch and it stops, then look again. You will probably find the piece stuck on either the driver or passenger side pushed back under the track. Mine had slid over to the passenger side and was easy to reach in and pull out once the roof pushed it back. Fixed the problem. The plastic piece was missing a section of the snapping tab that holds it in, so I stuck it next to the spare tire for safe keeping. does not effect the roof operation without it. Hope you are able to find the piece.