This is a A-161318A Ring Gear, Flywheel PN: 161318AMain Description As Following : A-161318A Ring Gear, Flywheel P.N: 161318A Dim A (1): 14.310" I.D.Dim B (2): 15.506" O.D.Dim C (3): 123 Teeth Found in Section & Models : Engine Parts > Flywheels and Ring Gears, White/ Oliver/ Mpl Moline TRACTOR: 1850 (DIESEL) Associated Items : New Also A-FRM-OLLATE, A-OL-O-1850, A-OL-P-1850, A-OL-S-18501950, A-SMO202 And : Inside Diameter: 14.310" Outside Diameter: 15.506" Teeth: 123 Width: 0.548"