leaking dishwasher

My dishwasher is leaking from somewhere above the motor. I have read that it could be the motor gasket (part #AP2908993), but it looks to me more like it is leaking around where the motor shaft enters the pump/impeller. When the wash cycle starts and the motor engages, water is flung off of the spinning shaft. I will probably replace the motor gasket, but can anyone tell me what seals, etc I would need to replace to stop a leak at the shaft location? Part numbers would be especially helpful. Thanks!