Try www.transmissioncenter.org and go to the search box(upper right of the page) and type in speedometer world. It's a sub section of the transmission center. They seem to carry a large inventory of parts and complete cables. If it's just the square end of the inner cable that needs replacing, try a local tractor dealer. A lot of them have crimp or epoxy filled ends available. Epoxy ones are easy, heat it up with a match, melt the epoxy and slide it onto the cleaned up cable end. Let it cool and away you go. Google speedocable repair kit and you should see a lot of options.