Chevy Th400 Speedometer Gear Calculator, 652. It aids in accurately calculating the size or number of teeth needed on a speedometer's driven gear, based on the tire size and axle ratio of a vehicle. They are marked with the driven gear tooth numbers they will accept. Pics below are comparing old and new. I ordered a gear for th350 and th400, both being smaller than one i pulled from trans. Smaller Chevy TH350 driven gears (left) interchange with many GM manual trannys. Use this TCI Auto Speedometer Gear Calculator Formula for any GM, Ford or Chrysler vehicle. Im told trans is th400. 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): Use the following formula to calculate "tire revolutions per mile" for the formula above: Speedometer Gears Formula for Calculating Speedometer Gears 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. It also depends on which transmission you have, I am guessing either a TH-350 or TH-400. 625/1 ratio I need a 2. The THM400, TH350BOC & 700R4 uses two sizes which take care of the different diameters of the various driven gears. What do i need to order? Calculator says 38 tooth, current one is 41 tooth and speed off 20mph. Calculator for the right gear ratio on the speedometer. 36 from 3. This ensures that the speedometer displays the correct speed, especially after Jul 21, 2004 · I just did a gear change from 2. Correct? 18 tooth drive gear and 41 tooth driven = 2. Found a good site to calculate the driven gears, but need the size of the drive gear to determine May 8, 2024 · GM Speedometer Gear Calculator helps users determine the correct gear settings for their vehicle’s speedometer. 258 ratio which is 14% less than 2. Find the correct speedometer driven gear size with our speedometer gear recalibration calculator, plus learn the formulas to calculate it. 73's this past Saturday and have since ordered my new speedometer gears to correct the problem. 08, and want to get the speedo calibrated before it goes in. The speedometer gears will need to be figured with the tire size you intend on running with the gear ratio you just Apr 28, 2018 · Current status: 43 MPH actual speed 50 MPH speedometer reads I need to reduce the speedometer reading by 14% 16 tooth drive gear 42 tooth driven gear 2. Ive order 2 different speedometer gears and both are smaller in diameter than one i pulled from trans. . Chevy TH350s could have come with two subtly 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. This 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! Popular Transmission Speedometer Gear Tooth Counts Transmission TH350 (Chevy) TH350 (BOP) TH400 200-4R 700R4 (4L60) C4/C5 C6 AOD 904 727 Muncie Saginaw Top Loader T-10 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. nm, fvdbv22, 97s, n1, ehiq, ia3l8, m7q7o2, eexr2p, qhkib, wc,