Delco Remy Starter - Troubleshooting Noisy Engagement

Usually when a starter is noisy during engagement you will have to remove it and check it over. Other things to check is the flywheel teeth that mesh with the starter drive gear. When the starter continually spins at high speed while starting then either the drive gear or the flywheel teeth are badly worn. What causes this is the operator engaging the starter while the engine is running. The starter below has a worn groove where the snap ring is positioned.

The machined groove should be as thick as the lock ring. You can see the groove has been worn lengthwise from the constant pounding of the drive gear during normal starting. The lock ring fits inside the washer on the shaft and locks the two together to provide a stopping point for the drive gear when the starter is engaged.

The only way to repair this condition is replacing the starter or the armature shaft. Either way the shaft itself cannot be repaired. The Mechanic has to decide which route to take in this situation.