spedo acting up

[natehanson_04]

Today my girlfriend took my truck to work cause here car is broken. She said that the spedometer started acting up? it said she was going 45 and she felt like she was going 80, so i drove it around town when she got home and it all seemed accurate, but felt like it was always a few seconds behind, for instance i would stop and the spedometer wouldnt go all the way down for a few seconds. Has anyone had experiance with anything like this? thanks

[98SurplusExpy]

Potentially the rear ABS Sensor (in your differential) failing.

It my help to pull it out and clean it off ... sometimes they get a build up of sludge adn it screws with its speed sensing ability.

[mohle]

Ditto on that diagnosis. I had to replace two on my 99 F350 V10. I talked to a mechanic about it way back when, and they sometimes install a rubber flap that hangs infront of the sensor on the diff. Apparently a common thing to break if you are going down gravel roads. Gravel will hit them almost like a bullet. Haven't had to replace one in my 06 yet, but haven't had to do the same type of trips yet either.

[natehanson_04]

thanks for the advice, ill give it a try