Sprocket, walker & shoe drive
CTPA-AH84243 Replacement Part to Fit:  John Deere For Models: 6600 SN <-105800, 7700 SN <-111900 Replaces: H80389. 15 tooth 50 chain 3.265" OD, 1.125" ID  Price:  $22.75  Buyers Club Price:  $20.47