Frequently Asked Questions About Torque Converters

All torque converters are similar in function. A torque converter is a device used in automatic transmissions to transfer torque from the engine to the transmission. It plays a key role in smooth vehicle acceleration, increasing torque at low speeds, and damping vibrations transmitted from the engine to the transmission.
It looks like a toroidal-shaped steel housing welded from two parts. However, a different type of torque converter is used for each transmission and engine. They differ in size, mounting, and construction inside. So for the same make of car with different engines, different torque converters will be installed from the factory. The external similarity of torque converters does not guarantee their interchangeability.

The description of the work of the torque converter is widely presented on the Internet. Let's focus on the main points.
A. The body of the transformer is rigidly attached to the crankshaft of the engine. At the first revolutions of the starter it begins to rotate and create a flow of working fluid (ATF), which transfers the torque to the turbine wheel inside the torque converter. The turbine wheel is connected to the transmission primary shaft and transmits torque to it. That is, the torque converter operates from the moment the engine starts.
B. The torque converter builds pressure within itself, but not within the transmission.
C. The torque converter is the primary source of heat in an automatic transmission due to the dissipation of some of the energy of the operating fluid (ATF) within it. This fluid works in a common circuit with the transmission and so heats the entire transmission.
D. When the gearbox selector is in the N position - the torque converter rotates at idle, without doing any work, with minimal heating of the working fluid.
E. When the gear selector is in the D or R position and we hold the car with the brake - the turbine wheel inside the torque converter does not rotate. In this case, there is a significant heating of the working fluid due to the rotation of the torque converter pump wheel and its flow under significant pressure inside this unit without doing useful work.
F. The most significant heating of transmission fluid inside the torque converter and, consequently, all gearbox assemblies, occurs during long intensive acceleration or slipping of the vehicle in snow or mud. This is dangerous due to overheating of the entire transmission with the risk of its failure.

Lockup: The weak point of most torque converters is the lockup assembly, which provides a rigid link between the engine and transmission. This unit is activated when driving in a straight line and, in modern transmissions, when shifting gears to speed up the process. It eliminates the energy losses that occur when torque is transmitted through the transmission fluid.
The friction pair in the lockup assembly is the friction material and the steel surface. Over time or due to a control system malfunction, this material wears or deteriorates. Wear particles get into the working fluid and spread throughout the transmission, clogging it, which can lead to transmission failure.
Bearings: Various types of bearings are used in a torque converter, including thrust needle bearings, ball bearings, and plain bearings. These components are designed to be highly durable, but they are still subject to wear and, in rare cases, can fail.
Seals: The lock-up mechanism of the torque converter is engaged or disengaged using ATF fluid. The pressure created by the control valve body manages this process. To separate circuits with different pressure levels inside the torque converter, seals like gaskets, O-rings, or PTFE rings are used. These components can wear out over time.
Bushings: Some types of torque converters use bushings, which can wear out or become damaged over time due to improper operation of the transmission control components or careless removal of the torque converter from the transmission housing.
One-Way Clutch (Overrunning Clutch): The torque converter's reactor is equipped with a one-way clutch that allows the reactor to rotate in only one direction relative to the transmission stator, where it is secured by a splined connection. This component is also one of the weaker points in the torque converter's design.

Disassembly and inspection of the internal components of the torque converter are essential when repairing a transmission. Since the torque converter operates within the same system as the ATF of automatic transmission, fragments of damaged or worn parts can be transferred from one component to another. Installing an old torque converter in a rebuilt transmission can introduce contaminants and debris into the new system, greatly increasing the risk of failure. The same applies to the cooler—it must be replaced after a major transmission overhaul. Thoroughly cleaning the cooler and torque converter without disassembly is impossible, as these components are non-serviceable.

A used automatic transmission is always a lottery. Our recommendations when replacing a used transmission are the same as when repairing a transmission - the torque converter should be opened, inspected, and all seals and friction elements should be replaced.

The lifespan of a torque converter is influenced by various factors, such as operating conditions, frequency of oil changes (ATF), total vehicle mileage, weight, power, and more. Under moderate loads and with regular maintenance, the average lifespan of a factory torque converter is comparable to that of an automatic transmission, typically around 200,000-250,000 km.

Torque converters in modern transmissions have become more vulnerable in the lock-up clutch due to increased demands for environmental standards and faster gear shifts. In older 4- and 5-speed transmissions, the torque converter lock-up was only engaged in the highest gear, minimizing wear. Now, it engages as early as the first gear and operates in a slipping mode for over 50% of the time, which increases wear and heats up the entire unit. To extend the life of the torque converter and the entire transmission, it is essential to regularly change the oil and filter every 50,000 km and check the ATF for antifreeze contamination. We can perform such a check with just 20 ml of transmission fluid.

No, it’s unlikely. The torque converter and its internal components rotate continuously once the engine is started. If the noise were coming from the torque converter, it would persist with the engine running, even in P or N. It’s rare, but a cracked drive plate (where the torque converter is mounted) might be the source of the noise. However, the torque converter itself is not typically the cause of the noise in this case.

If replacing the torque converter did not solve the problem, it might be due to superficial diagnostics. The torque converter issue could have been just a noticeable symptom rather than the main problem. Some control modules, especially on older models, might misinterpret sensor data, and the real issue could lie elsewhere, such as with engine sensors or even the ABS. Seek specialists who are well-versed with your type of transmission to avoid such errors.

No, this issue is more likely related to the automatic transmission. The torque converter transfers torque to the transmission, but if the car only moves after increasing engine RPM, it suggests that the friction pack of one of the transmission gears is slipping. The underlying cause of this problem needs to be diagnosed and addressed, but the torque converter is not the issue here.

There are two main reasons for water or coolant appearing in the transmission fluid (ATF): the vehicle being submerged in water and a breach in the transmission cooler's seal. Unfortunately, the presence of water or coolant in the transmission fluid (ATF) can lead to serious consequences. Even after changing the transmission fluid, malfunctions are highly likely to occur over time. In this case, a complete fluid change in the automatic transmission is pointless without fully disassembling it, repairing the torque converter, and replacing the transmission cooler. Coolant in the ATF alters the properties of seals, making them overly elastic and causing them to lose their functional properties. Additionally, water or coolant damages the friction material on the clutch plates in the transmission and torque converter, leading to the oxidation of metal control components in the valve body.
Therefore, contamination of transmission oil with foreign liquids generally requires a major overhaul of the automatic transmission, including replacement of all seals, friction packs, and repair of the torque converter.

With us! Repairing a torque converter requires specialized equipment to weld both halves of the casing with precise tolerances. We have this equipment, the necessary parts, and most importantly, extensive experience in repairing all types of torque converters. We also offer a wide range of parts for automatic transmissions and ATF.

• Upon receipt for repair, the torque converter is inspected for external damage (pump hub, pilot, mounting threads).
• The torque converter is then cut open using a lathe.
• If there is suspicion of coolant in the ATF or at the customer's request, a chemical analysis is conducted. A positive result indicates a breach in the transmission cooler and the need for its replacement.
• All elements of the torque converter are examined for damage.
• All seals and friction elements (lock-up clutch pads, friction and steel discs) are replaced with new ones.
• Damaged bearings and overrun clutches are replaced.
• The torque converter is assembled and inspected before welding, with control measurements taken and recorded in the component's passport.
• The torque converter is welded using specialized equipment, ensuring proper tolerances for the pump hub runout and internal thermal clearance.
• After welding, the final inspection of the pump hub runout and internal thermal clearance is performed, and the results are recorded in the component's passport.
• The weld's seal integrity is checked.
• The torque converter casing is marked with a unique number and packaged for transport.

The cost of repair depends on its complexity. Torque converters vary in internal construction. For example, the repair of torque converters like the Mercedes 9G-Tronic, Renault DP2, and certain Ford models may be significantly more labor-intensive compared to most ZF8HP** converters. Consequently, their repair costs will be higher than those of simpler converters. The cost may also be affected by the exclusivity of certain transmissions or severe damage to internal components, for which finding parts or a donor unit can be challenging. For detailed pricing, please contact our specialists by phone.  It can definitely be said that repairing a torque converter will be significantly cheaper than buying a new one, with a comparable lifespan.

A claim is not covered under warranty if the torque converter shows external damage due to improper installation (e.g., broken pump hub or bent pilot). If there is debris in the ATF but the internal components of the torque converter are intact upon inspection. If antifreeze is found in the transmission oil, we perform an oil analysis to determine its presence.
Another reason for rejecting a warranty claim could be if the inspection of the returned torque converter shows it to be fully functional and free of damage to internal components.

We stock over 200 types of rebuilt torque converters. If you bring or send us your torque converter and we have a matching unit in stock, we can sell you the repaired unit immediately or ship it after receiving payment.
If we do not have the specific torque converter in stock, we will repair yours. In most cases, this takes 1 day.

We have a system for shipping rebuilt torque converters, automatic transmission parts, and ATF via bus service. If needed, we can also arrange for a door-to-door courier. Delivery costs are not included in the repair price. For shipments of more than 3 units, bus delivery will be covered by us.

Our recommendation is clear—repair it. You may choose to install a used unit if it was removed from a working transmission, the fluid has no burnt smell, is clear and light-colored, and there are no external damages. However, we believe this is only sensible if the torque converter is obtained for free, the cost of removing and installing the transmission is no more than €50, and you receive 8-10 liters of ATF as a gift.

Yes, the problem could be with the torque converter. However, if the vehicle's mileage exceeds 100,000 kilometers, torque converter vibration is often the result of other issues, most commonly related to the valve body. The presence of coolant in the oil can also cause vibration in the torque converter's lock-up mechanism. Replacing the torque converter may temporarily solve the problem, but usually not for more than three months. Fresh friction materials in the lock-up mechanism of a repaired torque converter can compensate for the malfunctioning valve body or the presence of coolant in the oil, but only for a short time. To eliminate vibration long-term, consult qualified transmission specialists. Otherwise, you risk spending money on repeated repairs, torque converter replacements, and wasting time until you find skilled professionals.

Yes, this can occur if the one-way clutch in the torque converter's reactor is slipping. When this happens, the reactor rotates in both directions and fails to perform its function of increasing the torque transmitted to the transmission when starting from a stop. The engine struggles with this load and stalls.

This situation is similar to when vibration issues are addressed by replacing or repairing the torque converter. It might help, but there is a high likelihood that the problem will return soon. This approach is often used on cars that are being prepared for sale.

The torque converter is not as complex as other transmission components, so the likelihood of it being the sole issue after repair is low, but it’s still possible. Unfortunately, dishonest technicians often blame bad parts, poor ATF, or other factors. Check with the mechanic about what was done to the transmission. If the hydraulic control unit wasn’t disassembled and repaired, it’s more likely the problem lies elsewhere.

No, the torque converter and its internal components rotate continuously from the moment the engine starts. If the torque converter were the source of the noise, it would still be present when the engine is running with the selector in P or N. It's rare, but sometimes a cracked drive plate, which mounts the torque converter, can be the source of noise. However, in this case, the torque converter itself is not likely the cause of the noise.

Yes, we repair torque converters for tractors, loaders, trucks, and construction machinery. Despite the high factory-rated lifespan, these components can still fail. We have specialized equipment and extensive experience in repairing large torque converters. If parts like the pump hub are damaged and hard to source, we can manufacture them for specific models. Repairing torque converters for commercial and construction equipment is usually much cheaper than buying a new one, and delivery times for new units can be significantly longer than the repair time.