A call to the manufacturer (if they still exist) would do the trick. If not, call one of the RV salvage companies on the web. They'll tell you how much you have to replace to get the crank working again.
"Well Denny...looks like you'll have to replace the entire left half of your RV. There's good news though...we have one in stock".
2004 Winnebago Brave 34D with the usual add-ons