Output Shaft Speed (OSS) Sensor
WARNING: This page is about a different car, the 2008 Ford Pickup, 2008 Ford F550 Super Duty, 2008 Ford F450 Super Duty, and 2008 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The transmission 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, which are different than the teeth used for park function. The OSS input to the PCM is used for shift scheduling, Torque Converter Clutch (TCC) operation and vehicle speed. The OSS has bi-directional capability and has a digital output.