How can I remove the drive shaft sleeve for my Kitchenaid Food Processor ?

I have a 9-cup Kitchenaid food processor (kfp740) and I need to replace the motor drive sleeve because the plastic seems to have expanded just enough to prevent any of my attachements from sliding onto it. The replacement part is sold on line, but I cannot find any instructions on how to remove the old one.

I am afraid I'm going to break the drive shaft altogether if I am too forceful, but my attempts at pulling it off and unwedging it have proven to be unsuccessful.

What's the trick?

Thanks for your help.