One-Way Clutch-Planetary (Low)
WARNING: This page is about a different car, the 2003 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
The planetary (low) one-way clutch is a roller clutch that holds the planetary gearset in first gear, (D) and D ranges. During automatic coasting downshifts into first gear ((D) and D ranges), the planetary one-way clutch freewheels so there is no engine braking.