Simplicity 555 755 Snowblower Auger Gearcase 1686821SM, 1666416, 1666417 SAVEThis is a set of used auger gear cases from a Simplicity 755 snowblower, in great condition. Cases have 3/4 bushings and seals. These are the same cases used on the larger 560, 760, 860 etc machines. You would need to remove the current bushings/seals.