4th Gear: Powerflow
WARNING: This page is about a different car, the 2011 Ford Pickup, 2011 Ford F550 Super Duty, 2011 Ford F450 Super Duty, and 2011 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
In 4th gear, SSA is commanded ON by the PCM/ TCM to apply the forward (1,2,3,4) clutch. Shift Solenoid E (SSE) is commanded OFF by the PCM/ TCM to apply the overdrive (4,5,6) clutch. The forward (1,2,3,4) clutch connects the front carrier to the No. 3 sun gear and the overdrive (4,5,6) clutch is applied to transfer power from the input shaft to the rear planetary carrier, providing a 1.149 to 1 gear ratio.