C1 Drive Clutch
WARNING: This page is about a different car, the 2011 Lincoln MKZ and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The C1 clutch connects the front planetary carrier to the rear sun gear of the rear planetary set. The C1 clutch is applied in 1st (typical operation during engine braking), 2nd, 3rd and 4th gears.