95 2500 4*4 w/ automatic. Driving when suddenly lost overdrive. Speedometer on 0, tachometer working. Put new speed sensor on transfer case. Nothing changed. Any help would be appreciated!!!! Bob

 

I just bought a '94 2500 4x4 with auto. My speedo stays on zero most of the time but will jump around from time to time. Strange thing is the odometer works all the time. Cruse will not work either. The guy I bought the truck from gave me a speed sensor to install but I haven't done that yet. I was wondering how the odometer could be working if the speed sensor were broken?

 

It could just be a problem with the actual dash itself. Most of the time it ends up being the actual sensor itself though.

 

It was the sensor. Did not install it right the first time.

 

I haven't had a chance to look at mine yet. I'm over the road for the next two weeks. I have a new sensor sitting there so I'll try that first.