I used them and they seem to be the only option besides trying to repair it yourself without parts. I did not disassemble mine but soaked it in ATF for a few days and still could not manually move the paddle. Got the rebuilt unit back and it worked fine when I tested it. Won't be on the truck for quite a while so I don't know how well it will work in the real world. My expectations aren't that high since I drove these trucks as a kid. They did work great going downhill.
Chuck