2002 Ford Focus Speed Sensor

I know that the speed sensor on the transmisson is bad. Took the car to a mechanic who read the error. They wanted 142.00 to replace but local auto parts store got an aftermarket one for me for $50.00. I can do the work myself, but what I need to know or to see is a picture of this particular part. There are two of them one is non gear driven and one is gear driven. Even providing the VIN number to the dealer they couldn't tell me which one was needed. So I ordered both but no matter where I look I can't find when on the tansmission it's located and thus my issue. Can you please tell me which sensor I need and then how to replace it? I have a 2002 Ford Focus SE 5 speed manual transmission 2.0 L.