Key Features
- 21-tooth red gear follows Ford's factory color-coding system for manual transmissions
- Largest standard driven gear tooth count available for maximum speedometer correction
- Fits all TREMEC transmissions using Ford-style speedometer systems: T5, T45, TKO, TKX, and T56 Magnum
- Precision molded nylon construction for smooth, quiet operation and long service life
- Direct drop-in replacement--no modifications required
Description
Swapping to a 5 or 6-speed TREMEC transmission changes your final drive ratio, which throws off your factory speedometer calibration. This 21-tooth red driven gear lets you recalibrate your mechanical speedometer to read accurately with your specific tire size and rear axle ratio combination--no electronic tuner required.
Ford has used a consistent color-coding system for manual transmission speedometer gears since the 1960s: 16-tooth wine, 17-tooth white, 18-tooth yellow, 19-tooth pink, 20-tooth black, and 21-tooth red. As the largest tooth count in the standard range, this red 21-tooth gear provides maximum correction for applications with taller tires or numerically higher axle ratios. Each tooth of difference adjusts your speedometer reading approximately 5-6%, so selecting the correct count is critical for accuracy.
The driven gear installs into the speedometer housing on the tailshaft of your transmission, where it meshes with the drive gear on the output shaft. TKO, TKX, and T56 Magnum transmissions come from the factory with a 7-tooth drive gear, making this 21-tooth driven gear the correct starting point for common combinations like 3.55 or 3.73 rear gears with 26-inch or taller tires. Use a speedometer gear calculator with your actual tire diameter and axle ratio to confirm the correct tooth count for your build.
This gear is compatible with Ford T5, T45, TKO, TKX, and T56 Magnum transmissions. The driven gear works with both cable-driven and VSS-equipped speedometer systems--just swap it into your existing housing.
Kit Includes
- 21-tooth red speedometer driven gear (precision molded nylon)