4th Gear: Mechanical: Powerflow
WARNING: This page is about a different car, the 2012 Ford Pickup, 2012 Ford F550 Super Duty, 2012 Ford F450 Super Duty, and 2012 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.