Speedometer/Speed Sensor on 1998 Nissan Pathfinder

My speedometer dosent work and the engine light came on.
I had the dude at the local parts store put the diagnostic on my 98 pathfinder, 4x4, Auto... the diag. said Speed Sensor, so I get a speed sensor, take the old one out of the transfer case and put in the new one... still no speedometer and engine light is still on. Any thoughts???

Asked by for the 1998 Nissan Pathfinder