The torque converter is typically found deep within your automatic transmission, where it is largely neglected. This component is responsible for the gentle and efficient power delivery of the engine into the transmission.
Unfortunately, over time, these systems may suffer a lack of maintenance, and like any other component, will eventually result in a total failure. Detecting the torque converter symptoms early on can prevent costly repairs, reduce losses, as well as avoid the risk of car breakdowns.
Join me as we understand the symptoms of bad torque converters in depth so you can take corrective measures before it is too late, while ensuring seamless vehicle performance.
Torque Converter Basics
Simply put, a torque converter transfers engine power to the transmission. This converter is installed and mounted onto a flex plate in between the transmission and engine. The crankshaft spins the flex plate to create the conversion effect.
Right underneath the cover of the torque converter lies a pump with blades that functions like a propeller and runs in time with the engine crankshaft. As a result of this action, fluid from the transmission starts to pour onto the impeller’s blades.
The purpose of this specific blade structure is to be mounted on the transmission’s input shaft. The vehicle speed, along with the gear, is calculated based on the amount of hydraulic pressure produced within the transmission system and the steps taken in the other processes.
Why Does It Matter?
When cruising at 2900 rpm in 6th gear, the transmission will be cruising at just under 50 mph, and the engine and the transmission will be rotating at almost the same speed. This is a pretty seamless integration.
Consider when a driver approaches a set of traffic lights in a manual-transmission vehicle. More than likely, he or she will downshift to allow for a possible “go” scenario without a full stop.
As you come to a complete halt, your engine’s revolutions per minute will dramatically decrease. At this point, you will need to engage the clutch to disconnect the transmission from the engine to avoid stalling in the idle state.
With an automatic vehicle, we lack the privilege of manual separation. The labeled ‘automatic’ indicates the vehicle does everything by itself. This is where the torque converter offers its assistance.
A torque converter consists of the following main components: housing, fins, pump, and impeller.
The housing and fins are directly connected to the flywheel, so they are driven at the same speed as the engine.
As the pump spins, it cycles the transmission oil by forcing it to the outside and drawing more in at the centre through a vacuum. This then injects the transmission oil into the impeller, which will spin and drive the transmission as a stand-alone component without the engine.
Location
The position of a torque converter is more or less fixed depending on the drive configuration of the vehicle. In all scenarios, the torque converter sits between the engine and the transmission.
- Front wheel drive (FWD) vehicles have the torque converter placed towards the front of the vehicle, beside the engine. It’s located in a unit called transaxle, which is a combination of the transmission and differential.
- For Rear wheel drive (RWD) vehicles, the torque converter is located around the middles section of the vehicle, behind the engine. It serves the purpose of connecting the engine and the transmission, which then transmits the rotational power to the rear differential.
- In four-wheel drive (4WD) and all-wheel drive (AWD) vehicles, the positioning of the torque converter is the same as in rear-wheel drive (RWD) vehicles. It is placed between the engine and the transmission before power is sent to both the front and rear axles.
Causes Of A Bad Torque Converter
Torque converters are resilient, but not indestructible. Several causes could lead to wear and premature failure. Some of the common ones are:
- High Mileage: Torque converters, like any other piece of machinery, have a useful life. With high mileage, the moving parts of the torque converter will undergo damage due to the friction caused, leading to further problems down the line.
- Overheating: Overheating is a prime issue for automatic transmissions, including the torque converter itself. Many factors can lead to overheating, such as towing heavy loads, driving at extreme temperatures, or a faulty cooling system. Overheating can destroy the torque converter’s fragile seals and parts, rendering them useless.
- Contaminated Transmission Fluid: The function of the torque converter is to cool and lubricate the fluid. Any debris or metal shavings present will lead to excessive wear on the internal components of the torque converter and will hinder its smooth operation. Regular maintenance of your torque converter, including transmission fluid changes, is vital to its health.
- Defective Needle Bearings: The rotation and power transfer in the torque converter rely on needle bearings. These bearings may also get damaged or worn out over time, which can impact the operation of the torque converter, along with the generation of noise and vibrations.
- Worn-Out Clutch Lining: Engaging and disengaging the transmission is done through the clutch lining in the torque converter. It provides the necessary friction and grip. If the torque converter suffers damage, it will lead to a reduction in efficiency, shuddering, and slippage.
- Defective Torque Converter Solenoid: The flow of fluid to the torque converter clutch is regulated by the torque converter solenoid. A defect in this solenoid will cause problems in the engaging and disengaging process of the conversion.
Symptoms of a Bad Torque Converter
Issues with torque converters often overlap with the failure of an automobile’s transmission. This is a common misconception that can cost car owners thousands of dollars on repairs for transmission replacements or rebuilds.
Most people overlook the fact that the faulty component might be the torque converter, which is considerably less expensive to repair than the whole transmission.
Understanding the signs of a faulty torque converter will help avoid costly mistakes. Let’s look at each symptom closely:
#1. Slipping of the Transmission.
The faulty torque converter is unable to manage its fluid control, supplying too much or too little to the transmission. This results in to slip, which reduces the rate of acceleration and fuel economy. Fuel economy drops as a result of increased sweating.
In case of observing this behavior, make sure you check the levels of the transmission fluid as the slipping could be the result of low fluid. This additional check may save a couple of bucks.
#2. Rough Gear Shifts.
Another symptom is rough or delayed shifting. Unlike a clean and precise shift, the engagement may feel jerky and hesitant. This can result from either a low-pressure output to the torque converter or a malfunctioning shift solenoid.
As a temporary solution, you may notice better shifting with high RPMs because it boosts the converter’s pressure output. That said, this does not address the root of the problem.
#3. Inconsistent Vehicle Speed.
A malfunctioning torque converter may also cause random and erratic changes to speed without your foot touching the gas pedal. This occurs due to the changing hydraulic pressure that results in power delivery to the wheels becoming erratic.
As a driver, you may experience erratic changes in speed, acceleration and deceleration, changing RPMs, and hesitation during acceleration.
These symptoms are particularly hazardous for other drivers because speed and smooth cruising are essential in heavy traffic and even on the highway. To put it more plainly: don’t drive unless needed.
#4. Shuddering.
Your torque converter could most likely be the source of any shudders or vibrations felt between 30 and 45 miles per hour. The feelings are described as driving on a perfectly smooth road but encountering unexpected bumps. These shudders typically come without warning and go just as quickly, making it hard for a mechanic to solve the problem.
The engine is not appropriately giving power to the transmission through its torque converter, which is causing the shuddering. It is particularly vivid during light acceleration or when constant speed is maintained. It can be noticed while the vehicle switches gears as well.
It could also be a problem because of old tires or worn engine mounts. If the shuddering happens repeatedly at the same speed range and feels as though it is coming from the transmission area, it’s likely to be in the region of the torque converter.
Shuddering that occurs repeatedly at the same speed range and seems to be emanating from the transmission area is likely to be torque converter related.
#5. Unusual Noises.
A malfunctioning torque converter will create one or several of the following noises:
- Whining. You may hear a high-pitched whining noise with a power-steering pump low on fluid. This usually means there is a lot less transmission fluid available or there is some issue with the pump of the torque converter.
- Rattling. If a rattling sound is heard, it can mean that the clutch mechanism within the converter is deteriorating. When the car is parked, this rattle can be quiet. However, once the vehicle is put into gear, it tends to become more prominent and frequent.
- Humming or Buzzing. A persistent low low-sounding humming or buzzing while the engine is on might mean that the torque converter does not unlock properly.
- Clicking or Ticking. These sounds, particularly noticeable at idle, may mean the internal parts of the torque converter are worn or damaged.
- Grinding. If you notice a grinding noise when you change the vehicle’s gears, it could indicate that the torque converter is failing and shattering, which results in metal fragment contamination within the transmission fluid.
#6. Overheating Transmission.
Lack of efficient power transfer in the converter creates excess friction, generating heat. If not addressed, the transmission tends to overheat.
You may experience a burning odor, especially after driving, an increase in the transmission temperature (if monitored), as well as warning lights associated with transmission temperature on the dashboard.
Overheating should not be ignored, as it risks severe damage to the transmission. If, alongside other symptoms, you suspect overheating, it is best to stop driving the vehicle and have it towed to an auto mechanic.
The problem may be detected early with regular checks of the transmission fluid, as the fluid usually darkens or emits an unusual smell when exposed to overheating.
#7. Contaminated Transmission Fluid.
And by the way, a problem with a torque converter is easy to pinpoint by checking the transmission fluid level, as the fluid tends to get contaminated.
You may notice that the fluid level is lower than normal because a defect in the converter often leads to leaks. Be warned that contaminated fluid can cause further damage to other transmission parts, so heed this warning and make a service appointment as soon as possible.
Torque Converter Replacement Cost
Costs for the replacement of a torque converter differ significantly among providers, but on average, you are looking at $1,500 to $3,500, which includes labor and parts. The torque converter alone will cost you around $300 to $1,000.
However, if performed by a dealership, some vehicles will drive the price up to $4,000 to $5,000. This is one of those repairs where obtaining several estimates is far more beneficial.
Factors affecting the estimate include your vehicle’s make and model, type of parts used (OEM vs aftermarket, new versus rebuilt), the service provider (dealership, transmission shop, independent mechanic), and local competition influencing labor rates in your area.
If one were to look at the steps that need to be followed to replace a torque converter, the most cumbersome step is actually the removal of the transmission. This would make any DIY projects virtually impossible without the right tools in possession.
There is also the concern of possessing advanced mechanical knowledge. The effort that goes into replacing the system is itself a deterrent, considering that most professionals spend about 5 to 10 hours on the task.
Is it possible to repair or rebuild a torque converter?
From a technical perspective, it’s possible. Although in most instances, the torque converter can undergo some form of repair or rebuilding, in nearly all cases, it’s replaced. This is simply because the costs involved in labor are going to be the same, since that section will have to be accessed and worked on regardless.
If any component of the converter needs repair or replacement done on it, the converter is more time-consuming in labor (because of disassembly, reassembly, and testing) than if the entire unit is replaced.
Torque Converter vs Other Transmission Issues
Because torque converter issues so often mimic other problems, it can be difficult to pinpoint their exact cause. With that being said, consider using these clues to distinguish between the two:
Torque Converter Problems:
- Problems tend to happen at certain speeds or RPMs.
- During low acceleration, shuddering is more apparent.
- Most noises are apparent while idling or neutral, but are easier to hear.
- Issues may come and go, or worsen gradually over time
Transmission Problems:
- Slipping or grinding of gears takes place at every speed.
- You may completely lose some gears.
- Noises seem to be louder when switching between the gears.
- More prone to having a check engine light.
It’s more reliable to assume that issues with the torque converter appear spontaneously, while problems with the transmission are more stable. On the other hand, rotational problems start very subtly but worsen with time, while sudden problems develop out of nowhere.
Disregarding a torque converter problem for too long could result in needing to tackle other expensive repair problems, such as a damaged transmission.