Thanks.
My Haynes manual indicates that the code from my code reader means the output shaft speed is less than 60 rpm with vehicle speed above 15 mph (low output speed sensor rpm above 15 mph).
I went to the Dodge dealership and the mechanic said the sensor I needed was at the transmission, just prior to the engine. He did mention the rear sensor but said that the transmission speed sensor was probably the culprit.
The cost was $15.06 at the dealership.
If this doesn't work, I'll follow your advice.
Thanks again.