Do you hear your Chamberlain motor running but the chain is not lifting your door? It's probably your gear. To verify, remove cover off of motor head and and you see white shavings, the gear is your problem. You must apply a low temp lithium grease to each tooth of the new gear or it will shred within days.
20 Pack - Drive Gear for Sears Crafsman Liftmaster Chamberlain Garage Door Openers 1984-Current
Product Brand : Chamberlain
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