Fixing a speedometer that's reading wrong on your GM vehicle with a Powerglide, 200C, 375B, or 475 transmission? This TCI 21-tooth speedo drive gear set might be the solution. It includes both the drive gear and the driven gear, machined from high-quality materials to fit most popular GM transmissions. The gear is red (a common color-code for tooth count) and has 21 teeth, which affects how fast your speedometer cable turns. If your speedo is off after changing rear-end gears or tires, swapping this gear can correct it. The package size is about 6.37\ L x 3.5\ W x 1.12\ H. Installation varies by transmission, but it's a common repair for DIYers or shops. Make sure to verify your transmission model and current gear tooth count before ordering. A straightforward, affordable fix to get your speedometer accurate again.
