Output Shaft Speed (OSS) Sensor
WARNING: This page is about a different car, the 2005 Mercury Mountaineer and 2005 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The output shaft speed (OSS) sensor is a magnetic pickup, located at the park gear trigger wheel assembly, that sends a signal to the PCM to indicate transmission output shaft speed. The OSS sensor is mounted externally on the case. The OSS is used for torque converter clutch control, shift scheduling and to determine pressure control (PC).