Maxwell no longer supports their sailboat winches but I found the parts in Australia, apparently Maxwell sold the tooling to another winch company there. Below is their web address and information from an e-mail I recieved after inquiring about the part. You should be able to order them.
Hagar
http://www.arco-winches.com/
Part D145 is a stock item @ US$30.00/unit. Insured air mail is US$25.00.
When ordering send credit card details via 2 emails, 12 numbers followed by the remaining numbers, exp date and delivery address.
Regards
Allen Hutton.
Australian Yacht winch (Sales) Pty. Ltd.
4 Narang Place
St Marys N.S.W. 2760, Australia.