missing part is top rear of the window. There's a rivet and a broken piece remaining. Suspect some kind of guide was there that traveled in the track. I'll call an auto glass shop and see if they know what it was and have it.
Thanks for the part number. The dealer could order it but want $10 for one. I bought 25 on Amazon for $16 so will sell some on Ebay cheap. I've check the channel but no fragments there so it must have fell on the ground.There is a glass slide package part # 4339372. Google shows some hits. This is one with a picture.
This slide eventually wears and slips out of the channel. If it came off the glass, the slide may still be in the channel.
http://secure.terrys...ductID=JT.01570