Pinion Gear
CTPA-R120848 Replacement Part to Fit:  John Deere For Models: (4840, 4850, 4955, 4960, 8560, 8570, 8640, 8650, 8760, 8770, 8870 ALL FRONT / REAR) Used w/ R112936 & R74072 shafts. Replaces: R61423. 31 Tooth, 3.360" Wide  Price:  $187.17  Buyers Club Price:  $168.45