Service Brake System, Speedometer Jumps Around

[Deathdog]

2005 GMC Sierra 1500 4WD CrewCab 5.3. After in stalling a Transfer Case Encoder Motor (Successfully), the speedometer jumps around Brake, ABS lights on and DIC says Service Brake System and transmission is all over the place. Code C0055 (Rear Wheel Speed Sensor Circuit). I checked speed sensor on Transfer Case, seems unharmed. Wiring seems undisturbed. It seems unlikely that it just went bad? Any ideas?

 

To confirm, The Rear Wheel Speed Sensor is the sensor on the top of the Transfer Case?

[newdude]

Was the encoder motor and the transfer case indexed correctly?

 

When installing a new encoder, the transfer case has to be shifted in to neutral manually first, and the encoder indexed to match.  

 

Also, depending on what transfer case you have, there is a difference in how many output speed sensors there are (output speed sensor handles rear wheel speed sensor data).  If you have the RPO code NP8 AutoTrak case (NVG 246), there is two sensors.  If you have the RPO code NP1 electronic shift non AutoTrak case (NVG 263) it uses only one sensor.