Hi HO WELL CARS,
Here is where you can get one from on ebay. This is expensive. See my other post below.
http://www.ebay.com/itm/Lionel...bz_aR8vCk2EWMhpq1uhA
This is the gear for the Lionel O gauge one. There is another set of just the two gears if you do an e bay search of Lionel Intermodal crane gears, a bit expensive though. Good Luck I hope you get it fixed.