Hi, I am by far no mechanic. I used to work on cars back in the 70's, but these computer controlled things got me lost.

My question is this. My wife's 99 Durango's speedometer and odometer seemed to work just fine. It was correct with our GPS and with my odometer in my van. One day she called me and told me her Durango would only go about 20 MPH. We took it to a shop where they told us the speed output sensor was bad and had locked the trans into low gear. Fine, replace it while it is there. They did. Now I notice that the odometer is acting goofy. My wife works exactly 5.2 miles from home. So, a round trip should be 10.4 miles. Sometimes it is, some time its not. It seems that sometime the odometer will show additional mileage that should not be there. Its not always the same either, it varies. Could this be caused by a malfunctioning speed output sensor? No, my wife is not going to her boyfriends house (I hope!) She seems sincere about where she goes. The speedometer seems to be accurate and does not flutter up or down at all. Just the mileage seems weird. The one on the dashboard is in time with the one overhead. If its not this, what may be causing it?

 

there are two main sensors that control the speedometer and odometer(trip meters ect) the output speed sensor on the transmission, and the rear wheel speed sensor (also known as the rear wheel abs sensor) its located on top of the differential, however if it were me, i would take the truck for a week or so and see if it did it while you were driving it and if not then shes not being 100% honest.

 

+1 replace the ABS sensor on the rear diff.

 

Thanks. I will check in on that