Re: Odometer running 10 percent fast
You can determine what the differential ratio on the truck was when it shipped by checking the code on the inside jamb of the driver door. The axle code indicated there will tell you what the original gearing was.
...that being said, the odometer and speedometer both run off the same pulses, so if one of them is inaccurate, the other will also be inaccurate. There are products on the market that supposedly can be wired "in front of" the speedo/odo module, that read the incoming pulses and create a similar stream of pulses on the output that increase/decrease the frequency by a user-defined amount so that the speedometer and odometer read correctly.
2001 Ranger XLT 4.0L SOHC
Silver Frost w/ Dark Graphite interior
Summit 3" Body Lift
31x10.50 A/T tires
Explorer overhead console
Explorer auto-dim mirror
Aux1 & Aux2 inputs on factory AM/FM/CD/Cassette
Door-dinger silencer button
Seamless retractable roof and passenger-side ejection seat with steering wheel mounted controls and safety interlock