Yea, I had that problem on my 89 toyota...but when you go to 35's I guess you would have a problem...lol

 

+1 it is a percent off, not actual MPH. So at lower speeds it is less MPH off whereas higher speeds it is more MPH off.

The only way to correct this is to get a tuner or have the dealership flash your PCM, however I wouldn't let a dealership touch it because a "death flash" could be entered. As Sharps stated, a Hypertech or Superchips tuner can acount for gearing or tire size on a Durango so as you put the flash in yourself you enter the information. Then you get the better tune as well as the speedometer fixed.

 

Anyone live in Washington and have a superchip or hypertec I could use! Id be willing to pay alittle to use it! lol

 

they VIN lock so that once you use it on one truck you have to detune the first vehicle to use it on a second one that wont work.