Speedometer Drive Gear GM 15 Tooth Grey

The Speedometer Drive Gear GM 15 Tooth Grey from TCI is a precision replacement speedometer gear designed for GM 700R4 automatic transmissions. This grey plastic drive gear is engineered to maintain accurate speedometer readings by interfacing with the transmission's output shaft, making it essential for vehicles where factory speedometer functionality has been lost or degraded due to gear wear or replacement drivetrain modifications.

The 15-tooth configuration is calibrated for stock GM 700R4 applications and ensures correct speed signal transmission to the instrument cluster. Speedometer gears operate on a specific tooth-count ratio; using the correct tooth count is critical because mismatched gearing produces inaccurate speed readings—either reading high or low depending on the ratio variance. The grey plastic construction is OEM-specification material, providing the proper interface hardness without damaging the driven gear in the speedometer cable housing. This compact component weighs only 0.07 lbs and measures 3.5 × 1.25 × 6.15 inches, making it a direct bolt-in replacement requiring no modification.

Vehicle builders, transmission shops, and restoration professionals rely on correct speedometer drive gears when rebuilding or swapping 700R4 transmissions into classic vehicles, custom hot rods, or performance applications. Any driveline work that involves removing the transmission—whether for overhaul, modification, or replacement—presents an opportunity to verify speedometer gear condition. Worn or missing drive gears are a common source of non-functional speedometer issues in vehicles with high-mileage or previously serviced transmissions.