Hello there!, I'm still new to how this works so I'll try to make it short and detailed.
I recently purchased an Xbox 360 E off eBay, after the product arrived and was dusted off I noticed some issues. If the eject button on the console is used while the console is flat it will make an odd gear noise after closing before reopening the tray.
I asked the seller about it and they said they didn't notice any issues before shipping, furthermore if the console is in standing position the disc tray works fine. I've tried cleaning it off a bit more but still nothing, any idea on what it could be?