Causes A Damage to A Broken Hydraulic Tissue

automotive torque converter
Latest update date: February 02, 06

Torque Converter is an important part in cars using automatic transmission, playing the same role as the clutch in a manual transmission. It is located between the engine and the transmission, with the task of transmitting rotational energy from the engine to the transmission through a liquid (usually automatic transmission oil).

Hydraulic torque converters are a core component in automatic transmission systems, equipped on about 85% of modern cars according to statistics from the Society of Automotive Engineers (SAE) in 2024. The hydrodynamic mechanism in the torque converter allows torque to be amplified 2.5-3 times compared to the direct output from the engine, helping to optimize operating performance when the car starts and accelerates.

According to a 2023 report from the International Automobile Manufacturers Association (OICA), the cost of replacing a torque converter accounts for 15-20% of the total vehicle value, equivalent to VND20-50 million for the Vietnamese market. The study also showed that 65% of torque converter failures are a direct result of improper maintenance or poor driving habits.

This paragraph, Thanh Phong Auto will provide readers with a comprehensive view of the structure, operating principles, signs of trouble and especially the "tips" to help prolong the life of this important part. From there, helping car owners to be proactive in maintenance, saving significant repair costs and ensuring stable vehicle operation for a long time.

automotive torque converter
What causes car hydraulic torque converter failure?

Overview of Hydraulic Torque Converters

A torque converter is a mechanical device that transfers rotational energy from the engine to the transmission using oil as a medium. It allows the load to be separated from the main power source of the engine.

There are basically two common types of hydraulic torque converters:

  • Single-stage hydraulic torque converter: Consists of three basic components – impeller, turbine and stator. This type achieves 85-90% transmission efficiency at high speed, is popular on B and C class sedans and usually has a lifespan of 180.000-200.000 km.
  • Three-stage hydraulic torque converter: Uses three coordinated turbine blades, creating the ability to amplify torque up to 5 times the engine output. Achieving 80-85% transmission efficiency, this type is mainly used in SUVs, pickup trucks and heavy-duty towing/transportation vehicles.

Hydraulic torque converters are mainly used in cars using automatic transmission. In addition, they are also used in industrial transmission systems such as conveyors, coils, locomotives, lifting equipment, underwater moving equipment, etc.

Detailed Structure of Hydraulic Torque Converter

A hydraulic torque converter consists of five main components: impeller, turbine, stator, one-way coupling, and converter housing. Each component plays an important role in transmitting and amplifying torque. These components work together to ensure the efficient operation of the transmission system.

  • Impeller (pump wheel): The part is mounted directly on the torque converter housing and connected to the engine shaft, usually made of aluminum alloy or special steel. The impeller has a diameter of 200-350mm (depending on the vehicle type) and creates a high pressure oil flow of 70-150 psi when the engine rotates, operating similarly to a centrifugal pump.
  • Turbine: The part that connects to the input shaft of the automatic transmission, usually made of stainless steel or special alloys to withstand heat well. The turbine has 20-30 specially inclined blades to efficiently convert hydrodynamic energy into mechanical energy, achieving a conversion efficiency of 90-95%.
  • Stator: The part located between the turbine and the pump impeller, fixed on the gearbox housing. The stator has 15-20 flow vanes and directs the oil flow back to the pump impeller at an optimal angle, increasing torque and transmission efficiency by 2.5-3 times.
  • One-way coupling: A mechanism that allows the stator to rotate freely in one direction, preventing the stator from rotating in the opposite direction, operating at speeds up to 5000 rpm and optimizing torque amplification efficiency to 95-98%.
  • Converter housing: The outer shell is made of cast steel or aluminum alloy with a thickness of 3-5mm, enclosing and protecting the internal components, withstanding pressure up to 200 psi and working temperature of 80-120°C.

Operating Principle of Hydraulic Torque Converter

The hydraulic torque converter operates on the principle of hydrodynamic transmission, using transmission fluid (ATF) as an intermediate medium. This process allows the smooth transmission and amplification of torque from the engine to the transmission.

Hydraulic torque converter structure
How does a hydraulic torque converter work?

1. Transmission and torque amplification process

The process of transmitting and amplifying torque takes place in three main stages: pumping, transmitting and amplifying.

  • Pump Stage: When the engine rotates at 1000-2000 rpm, the impeller rotates and creates an ATF oil stream with a pressure of 70-150 psi and a flow velocity of 15-25 m/s. This oil stream is pushed towards the turbine with an impact force of 300-500N.
  • Transmission stage (Turbine Stage): The oil flow from the pump impeller impacts the turbine blades with a pressure of 50-120 psi, creating a torque of 150-250 Nm, causing the turbine to rotate with a transmission efficiency of 75-85%. The turbine is connected to the input shaft of the gearbox, transmitting rotational motion to the gearbox.
  • Multiplication Stage: The oil flow after impacting the turbine is led to the stator at a speed of 10-20 m/s. The stator changes the oil flow direction at an angle of 120-150 degrees and pushes it back to the pump impeller with an increased pressure of 30-50%. This process creates a torque multiplication effect of 2.5-3 times compared to the original torque from the engine, achieving an amplification efficiency of 90-95%.

2. Effect of engine speed on torque converter efficiency

Engine speed has a direct effect on the performance of the hydraulic torque converter.

  • At low engine speeds (800-2000 rpm): The speed difference between the impeller and the turbine is large (70-90%), creating a high slip ratio. Under these conditions, the stator maximizes its role in amplifying the torque by 2.5-3 times, creating a transmission efficiency of 60-70%, helping the vehicle to start and accelerate strongly from a standstill.
  • At high engine speeds (over 2000 rpm): The speed difference between the impeller and the turbine is reduced to 10-20%, the slip ratio is low. The stator now rotates freely in the direction of rotation of the impeller and the turbine thanks to the one-way coupling, reducing torque amplification. At high speeds (over 3500 rpm), the torque converter operates at 85-95% efficiency, similar to a conventional hydraulic coupling, transmitting rotational motion directly from the engine to the gearbox with minimal energy loss.

3. The role of transmission fluid (ATF) during operation

Automatic transmission fluid (ATF) plays four key roles in the operation of the hydraulic torque converter, with specific technical characteristics:

  • Hydraulic transmission: ATF is the main transmission medium with a viscosity of 7.0-7.5 cSt at 100°C, transmitting energy from the pump impeller to the turbine with a transmission efficiency of 85-95%. According to research by the Society of Automotive Engineers (SAE), high-quality ATF can improve transmission efficiency by 3-5%.
  • Specialized lubrication: ATF oil contains 7-12% special lubricant additives, lubricates moving parts with a coefficient of friction of 0.07-0.11, reduces wear by up to 65% compared to conventional oil and extends component life up to 200.000km.
  • Efficient cooling: ATF oil has a heat dissipation capacity of 0.13-0.15 W/m·K, helping to cool the torque converter, maintain a stable operating temperature of 80-120°C and prevent overheating that can cause damage.
  • Cleans and protects: ATF contains 5-8% detergent and dispersant additives, removing dirt and metal chips down to 5-10 microns in size, keeping the torque converter clean and extending the oil change interval to 60.000-80.000km.

What Are The Signs Of A Damaged Torque Converter?

According to statistics from the International Association of Automotive Engineers (IAM) in 2023, the warning signs in order of popularity include: vehicle skidding, vibration (45% of cases), contaminated transmission fluid, engine overheating (30% of cases), abnormal noise when braking, 15-20% reduction in fuel efficiency, and difficulty shifting gears. Early detection and treatment of these signs can reduce repair costs by up to 70% compared to when the torque converter has completely failed.

1. Vehicle slipping

Slippage occurs when the engine rpm increases but the vehicle speed does not increase accordingly. This indicates that the torque converter is not transmitting enough torque to the transmission. 

According to a 2023 study by the Institute of Automotive Engineers (IAT), this phenomenon reduces transmission efficiency by 50-60%, increases fuel consumption by 15-25% and is a warning sign that the torque converter needs to be checked within the next 1000-2000km.

2. Vehicle vibration

Vibrations can be felt when the vehicle is running at a certain speed or when shifting gears. The cause can be warped turbine blades, worn bearings or damaged components inside the torque converter.

According to a 2023 survey by the European Automotive Engineering Association, 78% of torque converter vibration cases were particularly evident when the vehicle was running at a speed range of 60-80 km/h or when shifting from 2nd to 3rd gear with a measured vibration force of 0.3-0.8 g at the steering wheel.

3. Contaminated gearbox oil

Normal automatic transmission fluid (ATF) is bright red to clear pink in color and has no burning odor; when the torque converter has a problem, the color changes to dark reddish brown then black and has a burning odor like burnt paper.

According to the Society of Automotive Engineers (SAE) 2022 standards, good condition ATF should be clear, free of particulate matter, and free of air bubbles when checked with the dipstick. When the torque converter is excessively worn, metallographic analysis of the oil sample will reveal copper (from the bearings) 75-125 ppm, aluminum (from the housing) 15-40 ppm, and iron (from the blades) 150-300 ppm.

4. Engine overheating

Inefficient hydraulic torque converter increases engine temperature by 15-25°C above normal due to 30-50% increase in slip, forcing the engine to work at higher rpm.

According to research by the Toyota Automotive Technical Center in 2022, when the torque converter has a problem, the energy transfer efficiency drops from 90% to 60-65%, forcing the engine to generate 20-35% more power to maintain the same vehicle speed.

5. Strange sound when braking

Strange sounds such as a hissing or squealing noise may come from the torque converter when braking. This could be due to a faulty one-way coupling or seized components inside the torque converter. 

According to a 2024 Ford Service Center survey, 85% of the time this sound occurs in three situations: when braking from average speed to below 3 km/h, when shifting from D to R, or when stopping with the engine still running.

6. Reduced fuel efficiency

Poorly functioning hydraulic torque converters increase vehicle fuel consumption by 15-30% due to high slip ratio and increased hydraulic friction.

Research by the European Institute of Automotive Technology (EAIT) in 2023 showed that when the torque converter efficiency drops from the standard level of 85-90% to 60-70%, the engine must operate at 500-800 rpm higher to maintain the same vehicle speed, leading to a significant increase in fuel consumption.

7. Difficult to shift gears

Difficulty shifting gears is a sign that appears in the stage of serious damage (70-80%) of the torque converter, usually due to unstable oil pressure (fluctuating 15-30% compared to the standard level) or uneven hydraulic flow. 

According to data from the ZF Transmission Research Center in 2023, when the torque converter is not working properly, the oil pressure transmitted from the torque converter to the transmission control unit is insufficient or unstable, causing the transmission control system to receive incorrect signals and leading to incorrect gear shifting decisions.

What Causes Torque Converter Failure?

Torque converters can fail due to a number of factors, including mechanical component failure (turbine blades/impeller, bearings), excessive operating temperatures, substandard or contaminated transmission fluid, improper vehicle use, and manufacturer defects.

automotive torque converter repair
What causes damage to the hydraulic torque converter?

1. Turbine blade/pump wheel failure

Damaged turbine blades or pump impellers typically come in three main forms: uniform wear (58% of cases), warping (25%) and cracking/scratching (17%), with material wear measuring from 0.3-2.5mm on the blade surface. 

According to a 2022 study by the Detroit Mechanical Failure Analysis Center, turbine blades typically wear the most at the edge with an average wear rate of 0.05-0.12mm/10.000km under normal use.

2. Poor quality bearings

Bearings in hydraulic torque converters are usually tapered roller bearings with ABEC-5 standard or higher, withstanding loads of 800-1200kg and working temperatures of 100-130°C. 

According to a study by the Japan Bearing Engineering Association (JBTA) in 2023, low-quality bearings typically have a surface hardness below 58-62 HRC (compared to the standard of 62-65 HRC), a concentricity deviation of over 0.015mm, and a radial clearance exceeding 0.025mm.

3. Operating temperature is too high

The normal operating temperature of the hydraulic torque converter is 80-95°C, but when it exceeds 120°C continuously for more than 30 minutes, it will reduce the viscosity of ATF oil by 45-60% and increase the oxidation rate by 3-4 times. 

According to a 2023 study by the American Lubricating Institute (ALI), every 10°C increase above 100°C will reduce ATF oil life by half and increase metal wear by 25-35%.

4. Substandard/dirty transmission oil

Gear oil does not meet technical standards or is contaminated. Dirty oil contains abrasive particles, causing wear and clogging of oil channels. Substandard oil does not ensure lubrication and cooling capacity. 

According to a 2024 study by the American Petroleum Institute (API), ATF contaminated with hard particles over 10-15 microns will accelerate material wear by 3-5 times, while substandard oil can reduce torque converter life by 40-60%.

5. Improper use of vehicle

Improper vehicle operation such as overloading, towing heavy trailers or frequent sudden braking. This puts a lot of pressure on the torque converter, leading to damage. 

For example, frequently overloading or towing heavy trailers increases the operating temperature of the torque converter and causes rapid wear.

6. Manufacturer's defect

Manufacturer defects are typically linked to three main issues: material defects (3% of cases), assembly process errors (45%) and design defects (35%), according to statistics from the US National Highway Traffic Safety Administration (NHTSA). Between 20 and 2018, there were 2023 major recalls related to hydraulic torque converters from leading automakers, affecting approximately 12 million vehicles worldwide.

How to Maintain and Extend the Life of Hydraulic Torque Converter?

To maintain and extend the life of the hydraulic torque converter, you need to perform regular maintenance, use high-quality transmission oil, drive properly, repair damage promptly, choose genuine spare parts and clean the cooling system regularly.

According to research from the Society of Automotive Engineers International 2024, applying 6 proper maintenance measures can extend the life of hydraulic torque converters by 40-60% compared to normal use.

Causes of car hydraulic torque converter failure
How to maintain hydraulic torque converter to extend its life

1. Periodic maintenance

Perform regular maintenance as recommended by the manufacturer. This includes checking and changing the transmission fluid regularly, checking the internal components of the torque converter and the cooling system. Transmission fluid should be changed every 40.000 – 60.000 km or 2-3 years of use.

2. Use quality gear oil

Use quality automatic transmission fluid (ATF), correct type and technical standards. Quality oil ensures good lubrication, cooling and cleaning ability. It is recommended to use ATF with Dexron VI or Mercon LV standards for new car models.

3. Drive properly

Drive gently, avoid overloading, towing heavy trailers or braking suddenly. This will reduce stress on the torque converter and extend its life. Avoid sudden acceleration or sudden braking when not necessary.

4. Timely repair

Repair any signs of damage immediately. Delays can lead to more serious damage and costly repairs. Take your vehicle to a reputable garage for inspection and repair if you notice the vehicle slipping or shaking.

5. Choose genuine spare parts

Use genuine spare parts when replacing. Genuine spare parts ensure quality and durability, compatible with the vehicle system. Hydraulic torque converters or replacement components should be purchased from reputable suppliers.

6. Clean the cooling system

Clean the cooling system periodically to ensure stable operating temperatures. A properly functioning cooling system helps prevent overheating and prolongs the life of the torque converter. The radiator, water pipes and cooling fan should be inspected and cleaned.

FAQ – Frequently Asked Questions

1. Can I test a hydraulic torque converter at home? If so, what tools are needed? 

Can be checked. Some external signs of the hydraulic torque converter that need to be checked are: color and smell of the gearbox oil, check for oil leaks. However, for more detailed inspection, you need specialized tools such as oil pressure gauge, fault diagnosis machine and need professional knowledge. See the article now: The car lacks transmission oil – signs, consequences & precautions when replacing.

2. Can the hydraulic torque converter be upgraded to increase performance? 

Yes, hydraulic torque converters can be upgraded to increase performance by changing the turbine blade design, stator or using lighter materials. Upgrading can improve acceleration, reduce fuel consumption on gasoline engines and increased durability.

3. What is the average life of a hydraulic torque converter?

The average life of a hydraulic torque converter ranges from 150.000 to 200.000km or 7-10 years of use, depending on operating conditions and maintenance regime.

4. Does the torque converter affect the fuel consumption of the vehicle?

Yes, torque converters do affect your vehicle's fuel economy. An inefficient torque converter can increase fuel economy.

5. What new technologies are involved in hydraulic torque converters?

New technologies related to hydraulic torque converters include: hydraulic torque converters with lock-up clutches, electronically controlled hydraulic torque converters, and hydraulic torque converters integrated with hybrid systems. These technologies help increase efficiency, reduce fuel consumption, and improve performance. 

See more articles: Top 10 most impressive modern car technologies.

6. Does the torque converter affect the vehicle's emissions?

Yes, the hydraulic torque converter does affect vehicle exhaust. An inefficient torque converter can increase emissions.

7. Which address is reputable for repairing/maintaining hydraulic torque converters in Ho Chi Minh City?

If you are looking for a reputable address for maintenance and repair of hydraulic torque converters in Ho Chi Minh City, Thanh Phong Auto is the top choice for you. With nearly 15 years of experience in the field of auto services, a team of skilled technicians and modern equipment, Thanh Phong Auto is proud to bring customers professional and high-quality car care services.

Outstanding advantages of hydraulic torque converter maintenance and repair service at Thanh Phong Auto:

  • Team of experienced and well-trained technicians.
  • Using modern machinery and equipment such as specialized hydraulic torque converter testing machines.
  • Committed to using genuine spare parts, ensuring quality.
  • Scientific maintenance and repair process, complying with manufacturer's standards.
  • Enthusiastic consulting service, detailed quote before repair.
  • Long term warranty, attractive after-sales policy.
  • Spacious, airy service workshop space, comfortable waiting area.

With the above advantages, Thanh Phong Auto deserves to be the ideal destination for your hydraulic torque converter "friend" to be taken care of in the best way, helping the car operate more smoothly and durably on every journey.

Hopefully, this article has provided you with an overview of the hydraulic torque converter, helping you better understand its structure, operating principles, and how to recognize and fix problems when they occur. Take care of and maintain the torque converter properly to maintain the performance and durability of your vehicle.

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3 Commentary

  • Le Van Tuan 22/09/2020

    Where to repair hydraulic tissue variables?
    Ae just helps

    Reply
  • The gearbox is hot and dry. when cooled completely, operate normally. The water tank has rinsed the pump. Can you give me advice when replacing the other gearbox with the same condition

    Reply
    • Miss Hue 24/11/2020

      Hi, you.

      Does your car have a oil cooler, if you see if the oil cooler is working, if not, check your oil cooler.
      Dear.

      Reply


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