- Torque Converter Problems: Symptoms & Replacement Cost
- What does the converter do?
- 6 Signs of Torque Converter Problems
- How to diagnose the problem
- Common causes of torque converter problems
- Torque replacement cost
Torque Converter Problems: Symptoms & Replacement Cost
A problem with a torque converter is often associated with a symptom of falling transmission. You might think that it has too high cost to eliminate the problem. However, in this article you will get to know when it is better to replace the transmission or when it is possible to save thousands of dollars and replace or rebuild only a malfunctioning torque converter.
What does the converter do?
Generally, it is a fluid coupling that connects the engine to the transmission and transfers power. It is located between them and bolted to a flex plate, which is engaged by the crankshaft.
There is a pump inside of the torque converter, which actually consists of a set of propeller blades. This set is coordinated with incoming engine shaft, due to the high pressure, it engages the last blade called an impeller.
The last set of blades together with the impeller is connected to the transmission shaft. The gears are shifted according to the amount of pressure power inside of the torque converter, so higher pressure leads to higher speed.
The speed of impeller is regulated by the engine shaft and the hydrodynamic circuit. When the car is not moving or the brake pedal is pushed by the driver, the impeller will be slowed while the pump will be still working. In such a way, torque converter performs like a clutch in manual transmissions – it makes possible to keep the engine running while a car is stationary.
In the moment when the transmission fluid is pushing the impeller blades, the pump is also engaged to continue the cycle. Since the fluid is currently flowing in an opposite direction, it has to be reversed in order not to stop the engine.
To do this, there is a third wheel called stator, it is located between turbines on the pump shaft. It has angled blades that can reverse the direction of the fluid when it is hitting the stator. When the vehicle is stopped, the one-way direction clutch reduces the speed and stops the spinning, that is how circulation is breaking down.
When the vehicle starts moving, the stator is unblocked and is free to spin. In the split moment the transmission fluid strikes back the freed stator, it engages the pump and multiplies the torque from the engine side. During this few seconds, more and more fluid is used in transmissions and it causes the movement. When the car is running, the stator is spinning in the same direction as other turbines, that is how the circulation is maintained inside of the transmission system.
When all transmission gears are engaged and the vehicle is performing at the cruising speed, lockup clutch disk gets activated, connecting the front cover and the torque converter to the impeller. After all, every turbine is working together in an appropriate scenario.
6 Signs of Torque Converter Problems
Shuddering
Sometimes the lockup clutch can become out of order and you can feel the shuddering at the 30-40 mph. You will notice it easily, the feeling is like you driving over a harsh road with myriads of small bumps. The main function of the torque converter is to switch on the direct drive when it becomes worn the gear changing may become difficult. The feeling doesn’t last for a long period and can disappear immediately, nevertheless, if you experience such feeling you should check the transmission.
Slipping
Since the main function of a torque converter is to change gears with a help of hydraulic pressure inside of the transmission. The slipping may be caused by a damaged fin or bearing. The slipping arises by the lack of fluid transmission and on the contrary due to the shortage. Moreover, you can feel also the lack of the acceleration and the reducing in the car’s economy. So, before visiting a service shop you should check the fluid levels.
Overheating
Check the engine lights whether there is no overheating, it is the most effective sign to warn you about the problems with the torque converter. If the converter suffers from the high temperatures, it can’t transfer the power from the engine to the transmissions. Such circumstances lead to the damaging of the internal components.
Contaminated transmission fluid
If the ATF is full of debris or other small parts it means that the system is already damaged. In this case, you have nothing but to replace the fluid and hope that everything is ok if the problem doesn’t disappear you should have your cat checked by the professional.
Higher Stall Speed
The “stall speed” is an appropriate stage on which the RPMs are quite high to transfer the power from the engine to the transmission. If the torque is not working properly, it won’t transfer the power into the pressure correctly. If the car suffers, it will take more time to reach the appropriate speed and to engage the engine, causing the increasing of the stall speed.
Unusual sounds
If you experience strange noise while driving, maybe your torque converter is malfunctioning. Some sounds you have probably experienced such as a ‘whirring’ from bad bearings or ‘clinking’ due to ill turbines.
How to diagnose the problem
There is a short algorithm how to detect the problem. Be attentive to the shuddering, slipping and other symptoms on the each stage.
- Start the car and run it for several minutes.
- Press the gas pedal several times.
- Push the brake pedal and then shift the car into the drive mode.
- Change gears slowly on by one.
- Drive the car and listen to all sounds carefully while shifting.
- Do not drive with a broken converter or do not reach the max performance.
When the torque fails, it disintegrates and emits small pieces into the fluid. The ATF circulates in the whole transmission system and damages the internal components causing a fatal failure. The service may differ from a torque replacement or the expensive transmission repair. To avoid such consequences drive the car off the road when it is safe and stop the engine.
Common causes of torque converter problems
Bad torque converter needle bearings
Needle bearings are used to turn the impeller, turbine, and stator freely. The bearings isolate the roaring parts from the housing. If there are problems with bearings, the power will be decreased and the noise will appear, also the transmission fluid will become full of metal debris.
Damaged torque converter seals
If you face the leaking problem from the bell housing, then you might have problems with a damaged converter seals. If the torque converter can’t hold the level of the fluid, it can’t transfer the power effectively. This leads to the overheating, shifting troubles, slipping and other issues.
Worn torque converter clutch
The automatic transmission has some clutches located one after another throughout the assembly. A torque converter locks the engine and switches the correct drive. If it gets burnt due to the overheating or jammed because of the distortion or contamination of the transmission fluid, then in every moment the car can get stopped in the gear.
Faulty torque converter solenoid
The solenoid is regulating the amount of fluid that the lockup clutch receives. If there are problems in measuring the ATF pressure, then the clutch will be not performing on the appropriate level due to lack or overfilling with fluid. It may result in the loss of direct drive function, bad gas mileage, and stalling.
Torque replacement cost
The cost of repairing sometimes can be higher than the replacement, so it is better to visit the service.
| Repair | Cost |
| DIY | $150 to $500 |
| Transmission Shop | $600 to $1000 |
The cost of the torque converter ranges between the 150 -500$, but the main thing is labor. The transmission has to be removed in order to examine the current status and to replace the converter, the process itself is very hard and time-consuming. Only a professional can say for sure what is wrong, the converter or the transmission itself.
Some tips on choosing a torque converter
- Call the dealership in order to get the best advice on the type or the model of your torque converter. You can also get this information from the manual or search on the internet.
- The torque converter’s stall speed must be of 500-750 RPMs lower than the max torque of the engine.
- A camshaft of less than 220 degrees duration if your car doesn’t require 2400 RPM stall speed.
- If you are an owner of a light car, it is better to install the 2400 RPM converter, because 2000 RPM needs more breaking efforts.
