If you didn't use the moonroof for a while it could be that the old grease has hardened or congealed in the tracks of the sunroof cable or has formed corrosion/rusting. that's what happened in my 03 Sequoia Limited. The grease got so hard that it was almost plastic and rusted into the tubing assembly. I'm guessing that you have never greased the moonroof assembly so that's some 8year old factory grease in those tracks. the best thing to do would be to take the whole thing apart, clean up the old grease and lube it with some fresh one.