You need to find out the manufacturer of the gearbox, there is normally a sticker under the seat pan, if it is a hydrostatic box it will be either Tuff Torx or Hydro gear, if it is a manual box it will be Peerless or Dana Spicer, once you have the info approach the importer of the relavent gearbox, in the UK hdro Gear is Henton & Chattell, Tuff torx is Tenterden Garden Machinery, Peerless is Henton & Chattell, and Dana Spicer you will struggle to find anybody.
Husqvarna man, June 2010