When I called Kitchen Aid Customer Service, they recommended sending the blender to one of their Service Centers for repair. Following their advise would have entailed not only a lengthy wait, but the expense of shipping and their repair. Searching the internet, I found videos on how to do it yourself, and it looked easy. I discovered the part available at AppliancePartsPro.com for a very low price, and placed an order. Shipping was fair and swift.
Directions arrived with the part. Removing the broken part required a bit more effort than predicted, but worked fine. I was concerned about marring the plastic surface of the blender, as well as possibly bending the threaded stem...but not to worry, the blender is built tough. Plenty of good directions made it quite easy, and quick, not to mention saving quite a bit of money by doing it myself.