My LiftMaster Gear sprocket broke off: Here how to replace it yourself

I Order my part from Amazon when you order your parts making sure parts number matches your or compatible with your

[@stephen2220]

You overtightened the chain! the chain should rest about 1/2" above the bottom of the rail, yours is sitting at the top of the rail! If you leave it like this you will run into the same problem you had before with the chain gear snapping off. You also need to grease the bottom gear as well as the main gear, I didn't see you mention this in the video.