Hey Guys, I haven't had this truck (F250 SD Xcab 2wd 5.4) but about a month and have been thinking the speedo was a little off. Today I finally put my gps in the truck and took a drive and here is what I found..... up to 45, it works within the acceptable 1-2 mph, but when I go to 50 on the speedo, I go to 60 by the gps. As I speed up and the gps gets to 65, the speedo has climbed back up to the correct readings of just a little slower than what the gps is reading. The speedo doesn't jump up, it just moves a little faster as it catches back up. Then it will stay within spec's up to as fast as I took it, 80-82. It does this everytime and is consistant. Does anyone have an answer? Or has anyone had a problem like this?

I did a search of the forum and about all I found was some people mentioned the speed sensor on the rear diff. messing up and causing erratic jumps in their readings.

Rick

 

I just changed that sensor today on a sd truck I recently bought. Could not find it in the books as a speed sensor. Its listed in the aftermarket books as an abs sensor. I have a connection at a parts warehouse. Mine was $20 out the door. It would not hurt to swap it and see.

 

Would that cause this problem? I figured it would cause it to go crazy all the way through the speed range not just in a 15 mph window.

 

Try cleaning your VSS sensor. It is located on top of the rear differential.