O5565AB 05565AB Starter Flywheel Ring Gear Fits Case S SC D DCOne New Aftermarket Replacement Flywheel Ring Gear Fits Case Tractors This flywheel ring gear mounts on the engine flywheel and engages the starter motor pinion to crank the engine. It is a direct aftermarket replacement Fits Case D series and S series vintage tractors and is compatible with the models listed below. Specifications Teeth: 112 Inside Diameter: 12. 972" Outside Diameter: 14. 164" Compatible Models Fits Case D Series: D, DE, DH, DI, DL,