rts oe speedometer gear, 23 tooth, for ford automatic c4 c5 c6 fmx aod, will fit t5 tremec tko magnum, driven gear, 3.9, each

This new speedometer driven gear fits C4 C5 C6 C10 FMX AOD transmissions. Tip: If you can determine whether your speedometer is reading too slow or too fast, it is worth noting that a lower # of teeth will cause it to turn faster versus a higher # of teeth to turn slower

Speedo Gear Suit 3.7-4.11 - C4 - C5 - C6 - C10 - FMX - Approx 25-27 Inch Tyre Size

This is a retro-fit 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