The following formula will work for any GM, Ford or Chrysler vehicle and is very useful when there is no established baseline from which to work from such as replacing a transmission in a vehicle that was purchased without a drive line.
# Drive Teeth x Axle Ratio x Tire Rev. per Mile 1001
= # Driven Teeth
Use the following formula to calculate the Tire Rev. per Mile for the above formula.
This is a retrofit gear to allow the speedometer to function with 3.73 and 4.10 rear end gears. Since the gear tooth pitch is slightly different than OE, the service life of this gear is limited to less than 25,000 miles.
