2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 283Get this manual
FINAL DRIVE 17Remove the eccentric cam assemblyInspect the cam (1) and bushing (2) for wear or damageReplace component as required19Remove the input shaft assemblyInspect the pinion gear (1) for chipped, broken, or missing teethInspect the input shaft bearing (2) for signs of wearReplace the input shaft cover O-ring (3) prior to reassembly1 3