I recently rebuilt the transmission in my Sports Six and made video's of the effort. They are on YouTube at https://youtu.be/WhSwCIAi7_0 https://youtu.be/_aDt-Gx9bbY If anyone is interested. It is a transmission from A Mark III GT6 but it is similar to all 3-rail transmissions used in Spitfires, Heralds, GT6's, Vitesses., and Sports Sixes. Edward Hamer Petaluma CA