Originally Posted by born2bahick

You Can get the part from your LBS. My guess is it will cost within Thirty dollars of the cost of a new Dérailleur

Originally Posted by cobba

Put the derailleur model into the product search on this page, the model details will be in small writing on the underside of the derailleur:
http://techdocs.shimano.com/techdocs/index.jsp
In the search results you should find an exploded diagram with parts and part numbers, this might help you to find the part or you could just ring up a local bike shop and tell them the part and part number you want to order.

Originally Posted by jjbod1

Jenson USA was selling Deore derailleurs for $16. not long ago. I snapped up 2. If they dont have them there, Ebay is your friend.