How To Test a Torque Converter

Testing & Diagnosing Torque Converters

Are you searching “how to test a torque converter”? If so, Roadrunner Converters can help! We put this torque converter diagnosis guide together to help you find out if your torque converter is good or bad.

Torque Converter Testing Steps

Not every one of us know everything there is to know about cars, and you may found yourself in a situation where your car’s transmission is acting up and you’re not exactly sure why it’s doing that. It could be a problem with the transmission, or the transmission could be perfectly fine and it could be a problem with the torque converter. Torque converter issues on a lot of older transmissions can be diagnosed by carrying out a stall-speed test. Below we have outlined how you can safely and easily conduct a torque converter test.

Step 1 – Take necessary precautions

It’s always advisable to contact your transmission or car manufacturer and ensure if whether it is safe to conduct the test.It is important because the stall-speed test can ruin a number of newer transmissions, and even a few older ones;the manufacturer will be able to guide you in this regard. When you do run the test, don’t keep it going for more than 5 seconds at a time. Keep in mind that vehicles with an anti-lock brake system or traction control do not support this test, and running it on vehicles with an electronically controlled transmission will set off the check engine light.

Step 2 – Get your car ready for the test

Ensure all fluids in the vehicle are in good condition before conducting the test. Ready the vehicle by chocking the wheels and setting the parking brake. Install a tachometer, if the vehicle doesn’t have one, that is visible from the driver’s seat.

Step 3 – Start the engine

Pressing the brake pedal all the way, turn the engine on and shift the transmission to drive. Remember to not release the brake pedal.

Step 4 – Press the accelerator

With one foot on the brake pedal, press the accelerator all the way for 2-3 seconds with the other foot. Be careful not the exceed 5 seconds or the transmission could blow out.The stall speed is the RPM the engine maxes out at.

Step 5 – Interpret the result

An RPM reading lower than your engine and torque converters specifications means that the torque converter need a repair or replacement. An unusually high RPM reading indicates a slip in the transmission, which will have to be investigated.

Diagnosing torque converter issues could be a challenge, but there are several signs you can look for, and a set of simple tests you can conduct to determine whether the torque converter is causing the problem in your car.

What Causes Issues in Torque Converters

There could be a lot of things that could cause problems in the torque converter. Below are some of the most common:

  • Matching the torque converter with a non-stick engine it wasn’t designed for can cause it to fail really quickly.
  • Towing cargo that exceeds the vehicles towing capacity of a long period of time can damage the torque converter.
  • Old and worn out internal vehicular components will also lead to failures in the torque converter.

Wear and tear in torque converters will cause the vanes to bend, resulting in slow shifting or failure to drive. A symptom of bent vanes is that the engine will rev higher than usual, with the sound turning normal as the system warms up. Torque converter issues are a possible cause of such issues in the vehicle.

Other Symptoms of Issues in Torque Converter

Some of the most common forms issues with the torque converter may show up in are highlighted below:

  • Shudder in the Torque – You’ll know this is happening if the engine block shakes or quivers even at a slight acceleration, and even on smooth surfaces. The cause of this issue is a torque converter failing to effectively distribute power for the transmission.
  • Bad acceleration as low speeds – Low power when driving at lower speeds indicates a torque loss caused by improper rotation of the stator.
  • Whirring sound when starting up the engine – When the one-way clutch within the torque converter wears, it starts making a whirring sound. But this sound could also be caused by the formation of vacuum bubbles in the fluid as the pump fails.
  • Higherstall speed – When issues in the torque converter worsen, it will take more time for the transmission to engage the engine, leading to irregular engagement and consequently, total failure.This problem can affect transmissions with lock-up converters more severely than it does others.
  • Loud grinding or clacking sounds – These are never a good sign. When being caused by the torque converter, it indicates that its internal mechanism is disintegrating. Stop driving immediately and call in a technician to assess the damage. If you keep on driving, you risk the converter circulating metal shards through the transmission, and you’ll end up having the whole thing replaced.

Testing for Bad Torque Converters

A rather simple test can determine whether the torque converter is failing.This is how to carry it out:

  • Turn the ignition key and start up the engine. Wait for a few minutes for the engine to warm up, then gently press the accelerator twice and rev up the engine. Once it returns to its idle state, press the brake pedal all the way and shift into drive. Keep an ear open for any lurching, clicking, or whirring sounds, which will all indicate an issue with the converter.
  • Note if the sounds occur as you shift through all the gears, one after the other, including the reverse gear. Any lurches or failure in shifting gears also indicate an issue.
  • Drive around for a while, noting if the gears shift slowly or fail to shift, if the vehicle lurches, or if any of the dreaded sounds occur.

Issues in the torque converter can easily be mistaken for other issues, which is why they are hard to diagnose. But assessing the symptoms will allow you, but more preferably the technician, to timely diagnose and repair the issue before a faulty transmission does more damage than it already has.

Buy Torque Converters Online

Think you have a bad torque converter? Buy new torque converters online at  Shop online or call us and we will help you select the best new torque converter for your vehicle, your needs, and your budget.  We build everything from high performance and stout towing to torque converters designed to help you get maximum fuel efficiency. No matter what brand of vehicle or goal we have the torque converters you need to get the most out of your car, truck or SUV.