Do you have tuning software?If you have a speed reading in you tuning software then the sensor is good.Something may have to be changed in the pcm so you get a reading.You also have to make sure the yellow and purple wires are connected to your pcm so the computer gets a reading.
GREEN WIRE: PIN 20 in the RED Connector (VSS)



PURPLE WIRE: PIN 21 in the RED Connector (VSS)



YELLOW WIRE: PIN 50 in the RED Connector (speedometer)


On my truck a 1992 5 speed manual the wires from the trans sensor green/bk and purple/white went to pins 20 ans 21 on red connector to pcm.I have 1999 gmc pcm and wiring harness.Pin 50 red connector went to speedometer.