Hi,
The transfer case is unique to UMM. If the case is not repairable, you will need to ask around in the UMM forums for anyone who has a spare. I bought one last year to replace my broken one. They are hard to find. Alternatively, you can get one from Portugal, from UMMonline4x4 or Pecas Umm. They both are happy to ship. Price may be high though.
Geoff