Th400 Speedometer Gear Calculator, Oct 17, 2025 · Th400 question I have just put a 3.

Th400 Speedometer Gear Calculator, Works with TH350, TH400, 700R4, 200-4R, Ford, and Torqueflite applications. May 29, 2021 · What is the correct speedometer gear size for a Th400 with a 15 tooth drive gear, 3. Find the correct speedometer driven gear size with our speedometer gear recalibration calculator, plus learn the formulas to calculate it. This method is purely calculations-based and you should always check your manufacturers specifications. Was wondering if there is a chart to know which color gear I need since it's kinda hard to use the calculator without dropping the tailshaft off my daily? Jan 11, 2026 · C3 Tech/Performance - Speedo Drive Gear in Turbo 400 - Hi, About to install a rebuilt Turbo 400 (orig trans) in my 71. The speedometer gear calculator assists you in calculating the size of the gear you need for your vehicle's speedometer. If in doubt use manufactures posted diameter. . Find the correct gear ratio of the speedometer for your car with this online tool. Calculate the correct speedometer gear for your vehicle using Monster Transmission's tool by entering drive gear teeth, rear gear ratio, and tire height. Use Monster Transmission’s Speedometer Gear Calculator to find the ideal driven gear for your setup. 08, and want to get the speedo calibrated before it goes in. (About 10ish mph) My TH400 has an electric speedo instead of a cable. Pics below are comparing old and new. Speedometer Pinion - tooth speedometer pinion required Overall Gear Ratios Jun 16, 2023 · Speedometer gears are crucial components located inside the rear of your transmission. Found a good site to calculate the driven gears, but need the size of the drive gear to determine Feb 26, 2018 · Here’s how to dial-in cable-driven speedometers. The accompanying charts show what gears were manufactured for each type transmission. Enter the axle ratio, tire height and driven gear teeth to get the tire revolutions per mile and the speedometer accuracy. Enter the drive gear tooth count, axle gear ratio and drive tire diameter to get the recommended driven gear tooth count. A vehicle uses the speedometer drive gear to estimate its speed based on the rotations of its tires. Calculator Instructions This calculator provides the necessary information needed in order to determine what transmission speedometer gear is needed in order to properly calibrate a speedometer. They consist of a small "driven" gear that meshes with a larger "drive gear" installed onto the transmission output shaft. And I assumed my speedo would be a bit off once I did it. To determine the correct gear ratio of the speedometer for your car, use the following formula to calculate the number of teeth on the driven gear (round to the nearest available gear): The speedometer gear calculator assists you in calculating the size of the gear you need for your vehicle's speedometer. 73 ratio in my 2WD truck. Th400 question I have just put a 3. Changed out the rear gear to 3. TCI® now stocks the most po Calculate the tooth count of the driven gear for different transmissions and speedometer gears. I ordered a gear for th350 and th400, both being smaller than one i pulled from trans. 36 from 3. These gears play a pivotal role in measuring your vehicle's speed and ensuring your speedometer provides accurate readings. Speedometer Gear Calculator Enter your tire size Tire diameter may vary slightly depending on the manufacturer. Enter tire size, axle ratio, and drive gear to get accurate results and minimize speedometer error. 08 rear end and 26" diameter tires? Robert Fornash Oldsmobile 442, 1966-1967 1y · Public Explore TCI Auto's speedometer gears designed for high-performance automatic transmissions, ensuring accurate speed readings and optimal vehicle performance. Driven Gear Tooth Calculator Enter your drive gear teeth, axle ratio, and tire diameter (from above or manual) to calculate the correct driven gear. What do i need to order? Calculator says 38 tooth, current one is 41 tooth and speed off 20mph. In GM’s case most of the parts are still available from the dealer or aftermarket sources. The following formula will work for any GM, Ford or Chrysler vehicle and is very useful when there is no established baseline from which to work from such as replacing a transmission in a vehicle that was purchased without a drive line. Oct 17, 2025 · Th400 question I have just put a 3. Im told trans is th400. Was wondering if there is a chart to know which color gear I need since it's kinda hard to use the calculator without dropping the tailshaft off my daily Jun 29, 2025 · Ive order 2 different speedometer gears and both are smaller in diameter than one i pulled from trans. wyw, be, w26j2tw, gw4, jnsqw0, tx, bxshawoi, ctl, rxc0jgm, xqby,