The current P/N for the chain case is AUC16953. You will need the four bolts that holds it in place as well as the key for the impeller shaft. I would also replace the roll pin in the drive shaft. JD Parts shows a breakdown of the parts.Does anyone have the part number for that chain case? I asume it is a bolt on switch?
You will also need a bottle of GL-5 lubricant for the case.
Note: you do NOT need part #24 if you have the newer style chain case.