Rear wiper arm replacement

What is your question?

I'm trying to replace the rear wiper arm on my 1995 Dodge Grand Caravan and it seems to have stuck to the motor drive hub. A small part came off the hub and is stuck to the arm itself at the fitting. The motor works fine, but will I have to order a new one to get the small part I need? I've tried lubing and prying it out, but it seems to be corroded together very well.