Ring Gear - Flywheel
CTPA-266142R1 Replacement Part to Fit:  Case/IH "For Models: M, MD, SUPER M, SUPER MD, SUPER W6, WD6, W400, W450, W6, 400, 450, (560, 660 ALL DSL ONLY)" 125 TEETH; 15.72" O.D.; .80" WIDE  Price:  $39.34  Buyers Club Price:  $35.41