It is located on the top of the transaxle.
1. Unplug the sensor harness connector.
2. Unscrew the retaining bolt and pull the sensor out of the transaxle housing.
To install: 3. Inspect the O-ring on the sensor; replace it if necessary.
4. Install the sensor into the transaxle housing. Be careful the O-ring doesn't dislodge from the sensor.
5. Plug in the connector.
I attached a picture of the sensor. Hope it helps.