Diagnostic code P0720 Output Shaft Speed Sensor Circuit
 

I recently started off driving my diesel while the engine was not warmed up yet. It felt like it didn't want to shift out of 1st gear (automatic trans). When it finally did, the check engine light came on. Outside temp was about 80 degrees. My OBD2 scanner gave the following diagnostic code:
P0720 Output Shaft Speed Sensor Circuit.

Report Date: 7-6-2007 (6:14 PM)
Vehicle Year: 2000
Vehicle Make: Dodge
Vehicle Model: Ram 2500
Vehicle Engine Size: 5.9L Diesel
Vehicle VIN:
Vehicle License Plate:
Vehicle Mileage: 87,100

Stored:
P0720 Output Shaft Speed Sensor Circuit


MIL ON
MisFire Monitor Complete
Fuel System Monitor Complete
Comprehensive Component Monitor Complete
Catalyst Monitor Not Supported
Heated Catalyst Monitor Not Supported
Evaporative System Monitor Not Supported
Secondary Air System Monitor Not Supported
A/C System Refrigerant Monitor Not Supported
Oxygen Sensor Monitor Not Supported
Oxygen Sensor Heater Monitor Not Supported
EGR System Monitor Not Supported

DTC for which Freeze Frame was Stored P0720
Calculated LOAD Value 2.75 %
Engine Coolant Temp 143.60 °F
Intake Manifold Absolute Pressure 31.60 inHg
Engine RPM 1152 rpm
Vehicle Speed Sensor 15.53 mph
Intake Air Temperature 109.40 °F
Absolute Throttle Position 5.49 %

Would this Speed Sensor unit cause the hesitant shifting. The truck seems to shift well after a couple of minutes. It's a 4 speed auto.
Thanks, Steve