When the tension drops, springs lead to the clutch to release. Evenly spaced ridges, termed splines, line the inside and out of doors with the clutch to lock to the gears as well as the clutch housing. You are able to read more about these clutches in How Automatic Transmissions https://rafaeljaozj.mdkblog.com/38829171/not-known-facts-about-clutch-plate