I tried glueing the gears but the glue would not hold. I did find that if you go to a hobby shop that sells drones and r/c helicopters, they sell bags of these gears for about $10. Of the 10 or so gears in the bag, a couple were just the right size. Take your broken gear from the carousel to a hobby shop and ask for help, and you should find what you need. The gears just press on to the shafts and are held in place by their tight fit.