The torque converter is an important component of your vehicle’s transmission. It transfers rotating power from the combustion engine to the load. Problems with the torque converter can thus cause many issues on your vehicle, including a drastic increase in fuel consumption and incapability of the vehicle to move under its own power among other things.
Signs of a Failing Torque Converter
There are several signs that you might have a torque converter issue:
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Shuddering
Usually, you notice your vehicle shuddering because it feels like it is vibrating. Your vehicle will vibrate even when you are not going very fast. The shuddering makes the vehicle lag and is easy to notice.
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Overheating
If your vehicle has a transmission temperature indicator, it will let you know when your vehicle’s transmission is overheating. If the vehicle transmission keeps overheating, you may also notice the transmission acting abnormally, or it may go into fail date and stay in one gear and not shift at all. When you experience these two problems, it could mean your torque converter is failing.
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Slipping between gears
A malfunctioning torque converter can have a shudder that comes from the transmission. The slipping occurs while you are driving or shifting gears, and it usually comes with some odd noises too. Automatic vehicles should shift smoothly between gears. You may feel shuddering and even slipping in overdrive when the torque converter starts malfunctioning.
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Contaminated transmission fluid
Contaminated transmission fluid can also be a sign of bigger problems inside the converter or transmission. Clutch material, bearing and bushing pieces, and a shiny metal flake appearance is an indicator that things are coming apart inside.
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Transmission fluid leak
Torque converter seals can be damaged easily or get worn out with time, thus they are a common source of transmission fluid leaks. If you see transmission fluid leaking, it an early warning sign that something is wrong and could lead to bigger problems if left ignored.
What causes a torque converter to fail?
A torque converter can fail mainly due to overloading. Overloading a converter can result in several failure modes, some of which can be dangerous:
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Stator clutch seizure
This is whereby the inner and outer elements of the one-way stator clutch permanently locks together, thus preventing the stator from rotating during the coupling phase. This type of failure is mostly precipitated by severe loading and subsequent distortion of the clutch components.
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Stator clutch breakage
The stator clutch can break from shock loading, causing the stator to freely counter-rotate in the opposite direction to that of the pump and almost no power transmission taking place. This kind of failure can be caused by a very abrupt application of power.
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Ballooning
This is whereby the shape of the converter’s housing is physically distorted due to internal pressure and/or the stress imposed by inertia. This can happen from prolonged operation under excessive loading, abrupt application of load, or operating the torque converter at very high RPM. In extreme cases, ballooning can lead to the rupture of the converter housing, causing violent dispersal of hot oil and metal fragments.
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Overheating
The seals that retain fluid inside the converter can get damaged due to overheating, causing the unit to leak and eventually stop functioning due to lack of fluid. This can happen from continuous high levels of slippage that eventually overwhelms the converter’s ability to dissipate heat.
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Blade deformation and fragmentation
Abrupt loading or excessive heating of the converter can lead to pump and/or turbine blades deformation, separation from the hubs and/or annular rings, or breaking up into fragments. This failure will result in a significant loss of efficiency, and produce similar symptoms to those of status clutch failure though less pronounced. In extreme cases, there will be catastrophic destruction of the converter.
How to tell if a torque converter is locking up
To tell if torque is locking up, see if you can get a feel for when the vehicle shifts. When you get to the point you can feel the vehicle shift even under light loads you will start to feel it lock up.
While accelerating, try counting the shifts. The vehicle shifts every time you are moving up a gear. If you have a 4-gear vehicle, it will feel like the transmission has 5 or 6 gears.
Another way is by looking at the RPM. When moving at a steady speed give the vehicle a little gas, you will see a rise in the RPM but the vehicle’s speed will not increase much. When the torque converter locks and you give the vehicle some gas the RPM will not rise until the car starts moving faster.
What does a bad torque converter sound like?
There are many different kinds of noises that can be made when a torque converter goes bad. First, there may be a whining noise that sounds like a power-steering pump with little fluid in it.
The assembly’s motor features a mechanism that has clutches. When the mechanism goes bad, you may hear a rattling noise. The noise may not be so loud when the vehicle’s in the park. However, once the transmission is put into gear, the frequency and volume of the rattling noise will increase, indicating problems with your converter.
Will a bad torque converter throw a code?
A faulty torque converter normally sets a Diagnostic Trouble Code (DTC), which causes the Check Engine Light to come on. Normally, a faulty torque converter clutch solenoid will set diagnostic trouble code P0740.
Below are other related diagnostic codes:
- P0741 Torque Converter Clutch Circuit Performance or Stuck Off
- P0742 Torque Converter Clutch Circuit Stock On
- P0743 Torque Converter Clutch Circuit Electrical
- P0744 Torque Converter Clutch Circuit Intermittent
The above DTC’s are generic codes that apply to 1996 and newer vehicles. The codes may not apply to all vehicles. Vehicle manufactures may use manufacturer-specific DTC codes that are different from these codes.
How much does it cost to fix a torque converter?
Most auto repair shops will charge between $600 to $1000 for a torque replacement job. If you are a DIY person and would rather do the replacement yourself, then it will cost you anywhere from $150 to $500 for a new torque converter.
The exact cost depends on the make and model of your vehicle.
Can a bad torque converter cause hard shifting?
If a fin or bearing in the torque converter is damaged, it can cause hesitation in the transmission shifting, or the transmission may slip out of gear entirely. This happens because the engine torque is not being efficiently converted into the hydraulic pressure needed to shift gears within the transmission.
Check this too: What Happens When Your Clutch is Damaged
When the transmission fluid is low or in poor condition it can also cause hard shifting. Lack of adequate lubrication within the transmission can cause several problems, including hard shifting. The fluid in your transmission should appear clean, light red in color, and somewhat transparent.
Can you replace just the torque converter in a transmission?
Yes, you need not replace the entire transmission if the problem is with the torque converter. However, the transmission will need to be removed so that the torque converter can be inspected and then replaced. Sometimes, the damaged torque converter damage other parts of the transmission. Have your mechanic inspect it too before closing up the car.