on a 95 4x4 chevy diesel with 6.5 engine what would the sensor on the transmission transfer case be called?

I think there's two of them. When the transfer case is in 4wd, the sensor on the top is triggered and the solenoid in the frontend is energized to engage the transfer case to the half shafts. I don't remember what the other one does.

On the output of the transfer case is the VSS- Vehicle Speed Sensor.