Once the pressure drops, springs result in the clutch to release. Evenly spaced ridges, known as splines, line the inside and out of doors from the clutch to lock in the gears and the clutch housing. You may go through more details on these clutches in How Automatic Transmissions Perform. https://clutchkereta20852.blog2news.com/33640528/the-ultimate-guide-to-clutch-plate