Signs of a Failing Torque Converter

If your automatic vehicle isn’t changing gears properly, you may want to think twice before tinkering with your transmission. The issue could be with your torque converter. Because a faulty torque converter directly impacts the transmission, vehicle owners often mistake issues with their torque converter as transmission problems.

A torque converter is a type of fluid coupling located between a vehicle’s engine and transmission. It transfers the engine’s rotational force into hydraulic pressure, which then supplies the necessary power required for the transmission to shift gears. If a torque converter starts failing, the transmission may have trouble changing gears or may take longer to engage the engine, which is why many people think that they’re having transmission issues when the problem really lies in their torque converter. To help you diagnose the root cause of your vehicle’s issue, check out these signs of a failing torque converter.


Perhaps the most obvious sign of a failing torque converter is if the gears in your vehicle’s transmission start slipping. When a vehicle’s gears slip, you will likely notice that the noise from your engine changes pitch randomly or that your acceleration is delayed. Such slipping often occurs when a torque converter’s fin or bearing is damaged. As a result of such damage, the torque converter won’t be able to generate an adequate amount of pressure to control the flow of the transmission fluid and switch gears properly. If there is too much or too little fluid in the transmission, the gears will perform unpredictably, and slipping is likely to occur.


When a torque converter fails, the resulting lack of fluid pressure may cause an inadequate amount of fluid to flow throughout the transmission. As a result, the vehicle’s transmission may start to overheat.

Your vehicle’s temperature gauge will likely indicate that overheating is occurring by flashing the transmission control unit light on the dashboard. Such overheating can start to damage the internal components of the vehicle’s transmission which may further prevent it from shifting gears. To avoid costly repairs, it’s important not to ignore that flashing light and get your vehicle checked out by a mechanic immediately.

High stall speed

High stall speed is another telltale sign that there is a problem with your vehicle’s torque converter. Stall speed refers to the amount of time between when your vehicle idles and when it starts moving after pressing down on the gas pedal. In other words, stall speed is the point where the engine’s revolutions per minute are high enough for the torque converter to transfer power from the engine to the transmission. If a torque converter is damaged, it won’t be able to effectively transfer the engine’s rotational force into hydraulic pressure, and a higher stall speed will likely result.

To determine your vehicle’s stall speed, you may consider conducting a speed-stall test. To do so, you must first install a tachometer in an area that is visible from the driver’s seat. Then, set your parking brake and place wedges of a sturdy material closely against the wheels of your vehicle to prevent movement. Next, press down on the brake pedal and push the throttle pedal to the floor for roughly two to three seconds. To avoid damaging your vehicle, you should never hold the throttle for more than five seconds during a stall test. Upon conducting the test, compare the stall speed on the tachometer to the manufacturer’s recommendations to see if the stall speed is unusually high.

It is important to note that conducting a stall test will place stress on your vehicle’s transmission and may cause damage if you aren’t careful. As such, you should make sure to research your vehicle to see if it can handle a stall test before conducting one. In addition, you should also check to ensure that your car’s transmission fluids are clean. Doing so will help you avoid causing further damage to your vehicle.


Another common sign that your vehicle has a faulty torque converter is if it starts shuddering. When a vehicle’s torque converter is damaged, it may start vibrating when you are driving at moderate speeds of around 30 to 45 miles per hour, even when you’re driving on a smooth road. Such a symptom is likely the result of an issue with the torque converter’s lockup clutch. When a lockup clutch is damaged, a torque converter loses its ability to help the vehicle transition smoothly to direct drive. Thus, you experience the bumpy shuddering sensation.

Transmission fluid contamination

Transmission fluid that is opaque, contains debris or sludge, or smells foul is a common indication of a faulty torque converter. As a fluid coupler, the torque converter uses and relies on transmission fluid to operate properly. As such, if the transmission fluid is contaminated, certain components of a torque converter such as the turbine’s fins or stator’s bearings will likely become damaged. To prevent such damage from occurring to the torque converter, make sure to check and change your vehicle’s transmission fluid on a regular basis.

Strange sounds

Strange sounds coming from your vehicle are almost never a good sign. If your vehicle is making unusual sounds, there is a good chance that there is something wrong with your vehicle’s torque converter. A common noise that is associated with a faulty torque converter is rattling which is caused by damaged clutches. Such rattling will likely increase in sound when the transmission is put into gear. In addition to rattling, a whirring or humming sound is another common noise that you may encounter when your vehicle’s torque converter goes haywire.

If your vehicle exhibits any of these signs of a failing torque converter, make sure to stop driving it immediately. A faulty torque converter can often result in significant transmission damage due to overheating or fluid degradation. As such, it’s important to replace your faulty torque converter as soon as possible. For superior quality replacement parts for your torque converter or transmission, check out our extensive online inventory at Transparts Warehouse Inc. If you require assistance determining which replacement parts you need for your vehicle, contact our dedicated sales team members who have comprehensive knowledge on all of our wholesale transmission parts.

Signs of a Failing Torque Converter