UNDERDRIVE Clutch
WARNING: This page is about a different car, the 2015 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.
The underdrive clutch is hydraulically applied in first, second, second prime, and third (direct) gears by pressurized fluid against the underdrive piston. When the underdrive clutch is applied, the underdrive hub drives the input sun gear.