If your Chamberlain, Sears Craftsman, or LiftMaster chain-drive garage door opener is making a grinding noise, slipping, or just won't move the door, the plastic drive sprocket might be worn out or broken. This is the replacement sprocket and shaft assembly (part number 41A5021) that fixes that common issue.
It's compatible with many 1/3 and 1/2 horsepower chain drive models from these brands. The kit includes the metal shaft with the new plastic sprocket already pressed on. Installation requires some mechanical skill: you'll need to open up the opener's motor unit, remove the old sprocket (often requires a gear puller), and install this new one. It's a classic DIY repair that can save you the cost of a whole new opener. Make sure to unplug the opener and disconnect it from the door before starting!
