JEGS 555-62091 Speedometer Drive Gear Features:

• Purpose and Role: Speedometer drive gears are mounted on the output shaft of the transmission and are responsible for initiating the mechanical rotation that drives the speedometer system. They engage directly with the speedometer driven gears to transfer motion.
• Gear Tooth Count: These gears come in various tooth counts that must be selected based on transmission type, axle ratio, and tire size. The correct combination ensures that the speedometer provides an accurate reading.
• Installation Location: The drive gear is installed internally on the transmission output shaft. Access usually requires partial disassembly of the tailshaft housing or rear transmission case, depending on the vehicle design.
• Compatibility and Tuning: Selecting the correct drive gear is crucial when modifying tire size, axle ratio, or transmission. It is often necessary to adjust both drive and driven gears to recalibrate the speedometer after performance upgrades.