GM-47680 crankshaft stopper is used to retain the flywheel when servicing the flywheel, balancer, and related components, as well as when setting engine timing. Once the starter is removed, GM-47680 is installed in its place. The toothed adapter and required spacer are placed onto the center bolt of GM-47680, and the assembly is placed into the starter opening. The starter bolts/studs are used to retain the body of GM-47680, and the center bolt/nut is tightened once its teeth are engaged in the ring gear. Unapproved methods may damage the flywheel.