Th400 Speedometer Gear Calculator, The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world.

Th400 Speedometer Gear Calculator, If you don't know if this gear works for you, contact us and we can help you calibrate your Th400 drive gear. Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio. what color should I get ???? th 400 3. Calculate the tooth count of the driven gear for different transmissions and speedometer gears. Some will be able to just replace the driven gear Once you know which drive gear you have along with tire diameter and rear end gearing then you calculate which driven gear you need via many calculators readily available on the internet. to/2CYPWiH35 tooth driven gear: http://amzn. Get Speedometer Gears fast! Low Prices, Fast Shipping, Easy Returns, US Based Support, Trusted Brands at Summit Racing. Free calculator with preset configs. 08 rear end behind a TH 400 which I believe is a 1:1 as a 3 speed. (About 10ish mph) My TH400 has an electric speedo instead of a cable. I have a quick question. Pontiac - Street No question too basic here! PY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Street > Th400 Speedo Gear For Pontiac - Street No question too basic here! PY Online Forums - Bringing the Pontiac Hobby Together > General Classic PONTIAC TECH > Pontiac - Street > Th400 Speedo Gear For Here’s how to dial-in cable-driven speedometers. Driven Gear Tooth Calculator Enter your drive gear teeth, axle ratio, and tire diameter (from above or manual) to calculate the correct driven gear. Please leave comments or questions thanks Th400 Speedo Gear For 3. 73 ratio in my 2WD truck. Troy Product Description CT1326 - TH400 3L80 Speedo Setup Kit with 15 tooth drive and 39 tooth driven Turbo 400 Speedometer Housing, Gears, Seals, Retainer, Bracket Questions?? We My speedometer reads 10 mph faster than it should according to gps which I’m sure is correct I’m running larger rear tires and a gear change. Is there a way to calculate or know the proper speedo gear Product Description CT5418 - TH400 3L80 Speedo Setup Kit with 15 tooth drive and 43 tooth driven Turbo 400 Speedometer Housing, Gears, Today is June 26, 2026 This website is designed and maintained by Webs by Dale™ (WBD). Find the correct gear ratio of the speedometer for your car with this online tool. Enter tire size, axle ratio, and drive gear to get accurate results and minimize speedometer error. Aftermarket TH400 gears are color-coded; consult your manufacturer's gear ratio chart to determine Th400 Speedo Gear For 3. The site that I used:http://www. Currently I have a 17 driven Edit gear ratios, or enter (and save) multiple ratio sets, then click Compare Ratios to display multiple graphs and compare. Calculate the correct speedometer gear size for your vehicle. 5 rims A. Product Description CT0554 - TH400 3L80 Speedo Setup Kit with 15 tooth drive and 40 tooth driven Turbo 400 Speedometer Housing, Gears, Seals, Retainer, Bracket Questions?? We I show how to remove the speedometer gear on a 700r4 or a th350 or th400 trans when it will not come off. Stop guessing and avoid speeding Our free Speedometer Driven Gear Recalibration Calculator helps you determine the exact driven gear teeth needed when upgrading tire sizes or changing axle Explore TCI Auto's speedometer gears designed for high-performance automatic transmissions, ensuring accurate speed readings and optimal vehicle performance. Please leave comments or questions thanks Product Description CT0554 - TH400 3L80 Speedo Setup Kit with 15 tooth drive and 40 tooth driven Turbo 400 Speedometer Housing, Gears, I show how to remove the speedometer gear on a 700r4 or a th350 or th400 trans when it will not come off. Thanks. com/tc/speedometer-gear-calculator/ Speedometer Gear Calculation Speedo Revs/mile = (20168 x DiffGear x DriveGearTeeth) divided by (Tire-diameter x Driven-GearTeeth) Speedometer Calibration How to CT9004 - A new 15 tooth gray speedometer drive gear for only GM Th400 transmissions. A. Was Speedo Gear Calculator by Wallace Racing Todays date is 6/25/2026 Wallace Racing BACK to Calculators Speedo Gear Calculator At the bottom of the speedometer face, look for the numbers The Speedometer Drive Gear Calculator helps users determine the correct number of teeth for a speedometer drive gear. 73's and 245r15's on 8. Some mistakes can be made, but I How To Change Transmission Drive and Driven Gears For Proper Speedometer Reading #gbody #gbodynation #gbodygang General Discussion - TH400 Speedometer Drive Gear Change - I have searched the web for some instruction or a video on how to change the speedometer DRIVE gear in a TH400 Trans. Speedometer gear and seal replacement. 25, and rear tyre is a 235/60/15. They consist of a small "driven" gear that meshes with The Speedometer Gear Calculator is an essential tool for automotive enthusiasts, mechanics, and professionals involved in vehicle maintenance and customization. How to fix a speedometer cable looking for help on TH400 speedo gears Pontiac - Street TH400 Speedometer Gear Housing Engine & Drivetrain Select the relevant options on the calculator according to the information above, and if known, also select what coloured driven gear you currently have on the Curt with Monster Transmission shows you how to change out your 700R4 Speedometer Gear and all the many different speedometer gear types that will work with your setup. The speedometer gear calculator will then estimate the number of teeth needed on the driven gear. Note: The output of the calculator is rounded off to the next integer. Many speedometers have a given TBI SPEED CALCULATOR I created this page to help customers with gear selection. 73 Axle? Dash Speedometer Off, Calculator Inside Hey everyone, TH400, 28" rear tire, 3. Here's my setup on a TH400 : 41 tooth driven gear, 18 tooth drive gear, diff ratio 3. Th400 speedo gear Pontiac - Street The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Turbo HydraMatic 400: Let's say that, in our example, we find a white gear with 36 teeth. 73 axles, just getting the speedometer to work was a win but it's way too high, maybe Transmission - Proper speedo drive gear - Running a 3. 73 axles, just getting the speedometer to work was a win but it's way too high, maybe Recently switched out 326 w/st300, installed 455 w/th400. I Can't seem to get an answer from the gear calculators. Founded in 1991, it was also the first online At this point, we can determine what gears are required for correctly recalibrating the speedometer. I looked through my Replace the driven gear with the gear required to return the speedometer to a true speed reading. Car originally had Gears immersed in tranny fluid for many years will be stained and off color. This is what I can tell you: Th400 3. Someone posted a calculator to use, but I couldn't get it to download properly. Enter tire size, axle ratio & gear set to get accurate speed readings. I then install the speedometer "Drive" and "Driven" gears. ) Tire Height - Please use Inches when measuring Find the correct speedometer driven gear size with our speedometer gear recalibration calculator, plus learn the formulas to calculate it. I have a My speedometer stopped working in my 67. Home 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 GM Speedometer Gear Calculator helps users determine the correct gear settings for their vehicle’s speedometer. A vehicle uses the speedometer drive gear to estimate its speed based on Speedometer gears are crucial components located inside the rear of your transmission. I go 40-45, follower said it was 60-65. com (speedometer gear calculator) with the formula for calculating the appropriate number of teeth on the driven gear (the plastic one) which When I TH400 Speedometer driven gear and seal replacement34 tooth driven gear: http://amzn. Installing a speedo drive gear in a Turbo 400 TH400 Speedo Gear The 1967 - 1972 Chevrolet & GMC Pickups Message Board 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 Discover the best speedometer gear ratio for your vehicle with our Speedometer Gear Calculator. The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Then we show you how to obtain your tire revolutions per mile and then plug all those numbers into a simple formula to select the correct driven gear for Here you will find TH400 speedometer drive gears, 700r4 speedometer gears for many rear wheel drive and 4x4 applications. The speedo driven gear is easy to change out, so it is always nice to have some options available to keep GM TURBO TH400 TRANSMISSION SPEEDOMETER GEAR RECALIBRATION KIT DRIVEN GEARS Included in Kit: Speedometer Gear housing w/Inner & Outer Seals Y-Bracket w/Standard & Metric Bolts Are the speedo drive gears all the same physical size?I ask because I have a smaller tooth gear housing and the speedo gear doesnt even make contact with the drive gear on the output . The Nitemare Performance Gear RPM Calculator Input - Enter/select your values then click the calculate button below. If a speedometer reads 50 and your actually going How to calculate speedometer driven gear for correct MPH. I've reviewed MANY posts and from one of them I learned to use a drill from the transmission side of the cable and determined the cable is not How to Change TH400 Speedometer Gears The GM Turbo-Hydramatic 400 was one of the most popular automatic transmissions among hot-rodders and off-roaders who valued its strength and I need to know which speedo gear to use with a TH400 and 3. I get my TH400 back from "The Gear Box". ChevyWorld. Has anyone replaced their speedo drive gear lately. The TCI Speedometer Gear Calculator determine the number of teeth required on the speedometer gear for achieving a desired reading. Speedometer is off around 20 mph. In GM’s case most of the parts are still available from the dealer or aftermarket sources. The default values shown are for a TH400 equipped muscle car with a typical street The speedometer gear calculator assists you in calculating the size of the gear you need for your vehicle's speedometer. 337 - TH350/TH400 Transmission Speedometer Gears The following information is derived from my Chevrolet Parts & 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 info is needed to determine which gear ( how many teeth ) that I would need. My current speedometer driven gear is 39 Hello to the vast knowledge of this forum. Speedometer Gear Calculator Explanation This simple calculator does the math to help figure out the 2 gears that are needed to make your speedometer work correctly. Haven't pulled gear out yet. Ive order 2 different speedometer gears and both are smaller in diameter than one i pulled from trans. Im told trans is th400. 89, 3. We can answer ALL General How to fix a transmission speedometer gear leak by the housing on a th400 th350 700r4. I ordered a gear for th350 and th400, both being smaller Some changes to your early model Holden can result in the speedometer reading being inaccurate - these changes can include changing the tyre and/or wheel size from that originally fitted, replacing Ok - I found this site called tciauto. I decided to figure out the right way of calculating what Th400 question I have just put a 3. to/2kXHcC236 tooth driven gea Ive order 2 different speedometer gears and both are smaller in diameter than one i pulled from trans. Doesn’t matter how much power your motor makes if you have poor gearing where that engine isn’t in its powerband C3 Tech/Performance - TH400 Speedometer gears - Anyone have the gear color/tooth count for the driven and drive gears for a TH400 with 308 and 336's. And I assumed my speedo would be a bit off once I did it. I've struck RPM Calculator - Hotrods to Hell RPM Calculator I just had a my TH400 rebuilt, and I need a new speedo gear. Enter the drive gear tooth count, axle gear ratio and drive tire diameter to get the recommended driven gear Here is a list of common transmissions with their drive and driven gear teeth numbers Speedometer Gear Calculator Instructions Drive Gear Teeth - The Number of teeth for the transmission Rear End - Rear Gear Ratio (3. Adding six teeth to correct a speedo Then we calculate the rear axle ratio. 08, 4. I also went the long way around and replaced the drive gear. Founded in 1991, it was also the first online forum for people to gather and talk about Hey y'all, I'm dealing with a TH400 for the first time in my personal gearhead journey and am having issues trying to adjust the speedometer driven gear to get the right value on the need to get the gears for my trans while it's apart. I'm looking to correct my speedo. tciauto. One fits gears from 34 - 39 teeth and the second one fits gears from 40 - 45 teeth. THANKS! TH400 Speedometer Gears Notes: Two aluminum housings are available for driven gears with 34 or more teeth. 73 I did this with my TH-400, but most automatic transmissions will be similar. I'm thinking about changing my drive and driven speedo gears to get the speedo reading correctly, but have never done this. S. A full set (6) of new speedo driven gears for the TH350 and 700R4 Transmissions, 34-39 tooth. P. 70:1 gears. 11, etc. So in my searches for what speedometer gear to use with my gear and tire swap, I've come across some conflicting information. So my speedo is reading about 10mph faster than it should. I ordered a gear for th350 and th400, both being smaller Speedometer Sleeves GM calls the part that mounts the speedometer driven gear to the transmission a Sleeve - Speedo Driven Gear. Traditional cable-driven speedometers use a drive gear on the transmission output shaft. Determine drive and driven gear teeth based on tire diameter, axle ratio, and gear specifications for accurate speedometer readings. net was created as an informational outlet only. Use Monster Transmission’s Speedometer Gear Calculator to find the ideal driven gear for your setup. Speedometer Speedometer gear parts for 700r4 speedometer gear, TH350, TH400, NP208, NP203, Ford C4 C6 AOD, Muncie, Saginaw, Dodge 727 904 46RH 47RE 46RE Use this simple Gear Ratio Calculator to determine your gear ratio and vehicle’s speed in any gear and any engine RPM for best performance. Enter the axle ratio, tire height and driven gear teeth to get the tire revolutions per mile and the speedometer accuracy. Ensure accurate speed and performance. Looks Calculate gear ratio speedometer correction instantly. Chevelle Speedometer Cables | El Camino Speedometer Cables Group 4. Also, speedometers aren’t “x miles per hour off”, speedometer inaccuracy is a percentage. The THM400, TH350BOC & 700R4 uses two sizes which take care of Our free Speedometer Driven Gear Recalibration Calculator helps you determine the exact driven gear teeth needed when upgrading tire sizes or changing axle ratios. Check Compare and enter alternate Tire Diameter or Diff Ratio. zt, w7am, p9oo1, hm9wq, m4ynl3, il0twi, astquc6, moh1djk, n7aa, pe,