Got everything apart on this Chinese puzzle assembly, couldn’t believe how filthy it was inside. As I was lifting the roller assembly out a small gear assembly dropped off the right side of the assembly and I can’t figure out where it goes. If I can’t get that part back where it belongs, then all this work was for nothing, I’ve got a big bag of printer parts and the cost of a new printer. Is this an HP ploy to force the purchase of a new printer?