The TCI 39 tooth speedometer drive gear fits GM 200C, 375B, TH425, 475, and 700R4 transmissions. It mounts on the transmission output shaft and pairs with a matching driven gear to give an accurate speedometer reading. The driven gear tooth count is calculated from the drive gear teeth, axle ratio, and tire revolutions per mile.
- Type: Speedometer drive gear
- Application: GM 200C/375B/TH425/475/700R4 transmission
- Drive gear tooth count: 39
- Location: Transmission output shaft
- Part number: 880012
FAQ
What transmissions does the TCI 880012 speedometer drive gear fit?
It fits GM 200C, 375B, TH425, 475, and 700R4 transmissions.
How many teeth does this speedometer drive gear have?
It has 39 teeth.
How is the matching driven gear tooth count determined?
Driven teeth equal drive teeth multiplied by axle ratio and tire revolutions per mile, divided by 1001. Tire revolutions per mile equal 20168 divided by the tire diameter in inches.

