Output Shaft Speed (OSS) Sensor
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The Output Shaft Speed (OSS) sensor is located on the extension housing. The OSS is a Hall-effect type sensor. The OSS reads the gear teeth on the park gear, different than the teeth used for park function. The OSS input to the PCM is used for shift scheduling, timing and Torque Converter Clutch (TCC) operation and vehicle speed. The OSS has bi-directional capability and has a digital output.