I had the same issue with our years-old 7520. The gear was pretty tight on the axle, and would turn most of the time, but not all... Like when it applied pressure against paper. I flipped the printer over and used a mirror to inspect.. eventually I found that the gear had a crack between two teeth. I didn't want to take it apart and struggled to get epoxy in the right place so I ended up cutting a hole in the paper tray. Figured I'd upload the images to help someone else know where to cut if needed. It's about 3/4” by 1 3/4”, cut with a Swiss army knife.. nothing special. Got me right where I needed to be.