Expedition 2WD V8-281 4.6L VIN W EFI (1997)
Speedometer Head: Service and Repair
1. Remove the original driven gear.
2. With Va, Vi, and To known, calculate new number of driven rear teeth.
Ts = Number of teeth on service driven gear.
To = Number of teeth on original driven gear.
Va = Actual vehicle speed.
Vi = Indicated vehicle speed.
VSS = Vehicle Speed Sensor.
NOTE: Design accuracy is: -2/+5 mph at 30 and 60 mph (-3/+8 kph at 50 and 100 kph).
NOTE: Use one of the following formulas:
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Ts = (Vi x To)/Va.
-
Ts = (To x new tire revolutions per mile)/(old tire revolutions per mile).
3. Round to whole number, dropping fractions less than 0.6, and rounding up if fraction is 0.6 or higher.
