when i push the button i hear a loud "clunk" then nothing. when i push the button immediately after the motor engages but the gear doesn't spin. thank you.
Take a real good look at that gear. Is it stripped. By "motor engages" do you mean the motor turns but the gear does not? I would have someone push the button while you stand under the opener with the cover off and try to find out where that "clunk" is coming from.
i'm the only one home right now so no help to locate the clunk, the gear is stripped, no doubt about it.