Bose cd3000?

I took apart my cd-3000 only to have a small piece come loose that I cant figure out where I need to put it once I get the new cd component. It is a small round black plastic piece that has a bracket attached with a hole in either side as if it would accept a screw.One side is flat, the other has a black plastic cog which moves slightly and a pink center that appears to have a pin hole in it. There appear to be NIF00 and Z650 imprinted on the flat back side. Please help!