Flywheel Ring Gear
CTPA-70226830 Replacement Part to Fit:  Allis-Chalmers For Models: W226 SN PU96714> W/ GAS ENG, (D17, 170, 175 ALL W/ GAS ENG) 139 Tooth, 13.125" I.D., 14.0625" O.D.  Price:  $31.29  Buyers Club Price:  $28.16