Dtc #1- P0720

2000 durango came out with this code using my hypertech programmer. Then I looked up this code and it says output speed sensor circuit. Could anyone tell me where this is located?
thanks Dennis

on the rear of the trans driver side. check the resistance of the sensor

Can anyone tell me the best way to check this sensor (ex. what the resistance should be), and should it be checked hot, cold or both.
Thanks.