After the engine, the gearbox is the second most costly and complex part of any automobile. So, hearing any strange noise from it is never a good indication and often denotes an expensive repair cost. The same, however, may be said about torque converter noise.
Even so, after reading this article, you will at least be aware of the possible reasons and the approximate cost of each solution. Here is everything that may be occurring within your transmission. However, before we get into further depth.
A worn-out bearing is the most frequent cause of torque converter noise at idle. It might be the thrust bearing for the torque converter or an output shaft bearing. The following possibilities include a loose torque converter, a broken flex plate, a failed torque converter, and a damaged gearbox fluid pump.
5 Tips for Torque Converter Noise & Fixes
1. Worn Out Bearings
The output shaft and thrust bearing are the two major bearings of an automatic gearbox that might make noise while idle. A typical ball bearing supporting the output shaft eventually wears down and begins to make a scraping noise like a wheel bearing.
You will only hear it if you are driving slowly since that bearing is an output shaft bearing, which means it is on the driveshaft side. Nevertheless, it is probably a thrust bearing if you only hear it while the vehicle is idle.
The thrust bearing, typically a flat needle bearing, is between the torque converter and the transmission gears. The torque converter will make a loud rattling at idle if this bearing dies.
The bearing must now be replaced, which is the only option but is difficult. Five to eight hours of work will probably cost you between $375 and $600, assuming an hourly rate of $75. Nonetheless, the bearing is at least affordable, costing $20 on average.
2. Loose Torque Converter
A loose torque converter indicates that the flex plate is not properly fastened to it. It is important to tighten the torque converter bolts to the proper torque specification, and it is also a good idea to use thread lock on the bolts. This is because these components are subject to many stresses and vibrations, and if the bolts are not properly tightened, they will most likely back out.
If so, the flex plate is being struck by the torque converter, which is what you can hear. The noise is most noticeable while the engine is idle and has been characterized as rattling, banging, and grinding.
In this case, removing the gearbox and tightening the bolts before the torque converter or the flex plate is harmed is best. However, there is a potential that the torque converter was not properly fastened down if you have recently had transmission maintenance done or within the previous six months. In this situation, you should file a complaint with the repair facility that handled the job.
Alternatively, because the transmission must be removed, you should expect to pay between $300 and $500 to fix the problem. Yet even so, spending twice as much for a new torque converter is still preferable.
3. Broken Flex Plate
Apart from a manufacturing flaw, there are many reasons why the flex plate could fail, all involving human error. For instance, as we said previously, the flex plate might break if the torque converter is not correctly fastened. Yet in this instance, it is also possible that the bolts securing the flex plate to the crankshaft are loose. Nonetheless, misalignment of the transmission and engine due to missing alignment pins on the mating bolts for the gearbox and engine remains the most frequent reason.
A fractured flex plate will now generate a noise that may be characterized as clunking, rattling, grinding, and metal-on-metal vibration. Also, a replacement flex plate will cost between $100 and $200 if it turns out to be damaged. Moreover, labor costs should run between $600 and $1,000. It does not harm to ask your technician if he would at least offer you a discount since if you have recently had transmission work done, there is a good probability the flex plate is damaged due to a human mistake.
4. Torque Converter Failure
One of the many symptoms of a failing torque converter, which may manifest in certain circumstances while driving, is noise at idle. Additional signs include the car trembling, sliding gears, refusing to change ratios, hesitating to accelerate, etc. It is important to diagnose thoroughly to ensure that another factor is not the source of the torque converter issue. Even so, the cost of the repair will be high if it turns out that the torque converter has failed.
It may take five to ten hours to replace a torque converter, which costs $375 to $700 in labor costs at an average hourly rate of $75. A new torque converter starts at $300 and may cost up to $700 or more, but a remanufactured torque converter will cost between $120 and $300 and come with a one-year warranty. The final price averages out to be about $800.
5. Transmission Pump Failure
The transmission pump moves the transmission fluid through the cooler and around the gears. The pump, however, may create various sounds when it breaks since it is a mechanical component with its gears.
The most typical sound is a loud, high-pitched whining that becomes louder as engine speed rises. And if you do hear that, do not drive your vehicle until it has been fixed since the likelihood is strong that if you do, you will swiftly wreck the whole transmission.
However, because the ease of access varies so much across various autos, it is difficult to estimate how much it will cost to repair a gearbox pump. Nonetheless, it may range from $400 to $1,400, with the lower figure corresponding to smaller cars and older trucks and the greater amount corresponding to newer automobiles and expensive European brands. But this page has further information on how much it will cost to replace a transmission pump.
What Signs Point to a Torque Converter Failure?
The transmission’s refusal to change ratios is the principal sign of a failed torque converter. Additional signs include sliding torque converters, which implies they are not sending power to the wheels, and generally poor performance. In addition, you can notice transmission fluid leaks and see a check engine light because the transmission is overheating.
Can you fix the torque converter?
Certainly, a torque converter can be fixed, but only expert businesses can do this. Several specialized instruments, including a torque converter cutter, welder, balancing equipment, piston bonders, etc., are required to repair a torque converter. Also, it implies that the cost of remanufacturing a torque converter is high.
Why Would You Use a Flex Plate?
The torque converter and the engine are joined via a flex plate. i.e., the torque converter is bolted to the flex plate on one side and to the crankshaft on the other. The flex plate replaces the flywheel in a manual gearbox engine, which also features gear teeth on the edge for the starting motor.
What Can Happen If You Drive With a Faulty Torque Converter?
When a torque converter fails, driving may seriously harm the remainder of the gearbox unit and potentially the engine. Therefore, you should avoid operating a vehicle with a damaged torque converter since it may cause the vehicle to decelerate spontaneously or, even worse, surge suddenly.
What Might Produce Whining Noises from a Transmission?
The transmission fluid pump, not the torque converter, is the source of whining sounds in a gearbox. In essence, it denotes a low level of transmission fluid or a blocked fluid line that deprives the pump of fuel. That could also indicate that the pump is malfunctioning, however.
What Are Some Frequent Reasons for Torque Converter Shudder?
Low or old, polluted transmission fluid is the most frequent cause of torque converter shudder. The clutch pack discs grabbing on one another without having enough oil coating between them to make the engagement smooth causes a shudder you can feel. The answer, in this case, is to top up the fluid or replace it. Moreover, worn-out or broken clutch discs may be the second factor.
Do Torque Converters Spin During Idling?
Since a torque converter is mounted directly to the engine, it does indeed spin at all RPMs. The torque converter’s turbine component, on the other hand, is linked to the gearbox and the wheels through it. As the wheels are not turning at idle or at any other RPM, the torque converter turbine does not spin.
What Causes Noisy Transmission While Accelerating?
Low transmission fluid and increased gear friction are the most common causes of a loud transmission as you accelerate. Yet it may also be due to worn-out bearings, which produce a grinding or growling sound.
Conclusion
In the end, three unique tones distinguish transmission noise at idle. The first of them is a low-pitched growling or buzzing sound that comes from worn-out transmission bearings. The second and most typical problem is rattling, which might be brought on by a damaged flex plate or a loose torque converter.
The final and loudest is whining, which results from a damaged transmission pump or blocked transmission cooler lines. Ideally, this last step simplifies identifying the potential reason; if it does, go back and determine how to repair it or how much it will cost to solve it.