Whirlpool impeller

I have purchased an impeller (part #AP3738238) for my dishwasher. The old part that came off has a shaft on the back that the new part does not have. Has whirlpool changed this part? What are my options?

Yes, Whirlpool has changed the design and the part number for this kit, but I did not get clear which shaft are you talking about. The impeller threads onto the motor shaft and the shaft on another side of the impeller goes into the chopper.

Gene.