What Are the Three Members of a Torque Converter?
The three primary members of a torque converter are the impeller (pump), the turbine, and the stator (also called the reactor). Together, these hydrodynamic components transfer and multiply torque from an engine to an automatic transmission, enabling smooth vehicle launch and gear changes without a manual clutch.
The Three Core Members Explained
The following list identifies the three members of a torque converter and outlines what each one does inside the assembly.
- Impeller (Pump): Attached to the engine’s flexplate and driven directly by the crankshaft, it slings transmission fluid outward via centrifugal force, starting the fluid flow that transmits torque.
- Turbine: Connected to the transmission input shaft, it receives the high-velocity fluid from the impeller; as the fluid pushes the turbine vanes, it spins the input shaft and drives the gearbox.
- Stator (Reactor): Positioned between the impeller and turbine on a one-way clutch, it redirects return fluid at low speeds to reinforce the impeller’s rotation, multiplying torque; at higher speeds, it freewheels to reduce drag and improve efficiency.
Together, these components create a closed-loop fluid circuit that can multiply torque during launch and transition to efficient coupling as vehicle speed increases.
How They Work Together
At low vehicle speeds, the engine-driven impeller accelerates transmission fluid toward the turbine, which turns the transmission input shaft. The returning fluid would oppose the impeller, but the stator re-angles this flow, boosting impeller effectiveness and increasing torque at the turbine—this is torque multiplication. As turbine speed approaches impeller speed, the stator’s one-way clutch allows it to freewheel, reducing resistance and improving fuel efficiency.
Torque Multiplication and Efficiency
During initial acceleration, torque converters can produce a multiplication ratio typically in the range of about 1.8:1 to 2.5:1, depending on design. This extra thrust aids vehicle launch without a conventional clutch. Once speeds equalize, the converter behaves more like a fluid coupling with minimal multiplication and lower slip.
Modern Enhancements: Lockup Clutch
Most modern automatic transmissions add a lockup clutch inside the converter to eliminate slip at cruise, improving fuel economy and heat management. While important, the lockup clutch is not one of the three fundamental members; it overlays the classic impeller–turbine–stator trio to create a direct mechanical link at steady speeds.
Practical Notes and Symptoms
Recognizing torque converter issues can help prevent transmission damage and costly repairs. The list below highlights common warning signs drivers and technicians watch for.
- Shudder or vibration at steady speeds, especially during lockup engagement
- Delayed or weak acceleration off the line (poor torque multiplication)
- Overheating transmission fluid or frequent high operating temperatures
- Slipping sensation, flare, or engine revs rising without proportional vehicle speed
- Contaminated fluid with excessive debris, often indicating internal wear
If these symptoms appear, inspecting fluid condition, checking for diagnostic trouble codes (often related to the torque-converter clutch solenoid), and verifying lockup operation are key steps before deeper mechanical service.
Summary
The torque converter’s three members—impeller (pump), turbine, and stator (reactor)—work in concert to transmit and multiply engine torque to the transmission via fluid dynamics. The stator’s redirection of fluid enables torque multiplication at low speeds, while modern lockup clutches add efficiency at cruise but are not part of the core trio. Understanding these components helps diagnose drivability issues and maintain transmission health.
What are the components of a converter?
The basic components of the converters are diodes, transistors and thyristors. – Cyclo-converter – A cyclo-converter is a single-stage (AC-AC) converter and converts AC with a constant frequency directly to an AC with a varying frequency, as required for the desired motor speed.
What is the drive member of a torque converter?
Impeller
Impeller. Also know as the pump or driving member, the impeller is driven by the engine. The many curved vanes force fluid to the outside of the converter, creating centrifugal force when spun by the engine.
What is a stage 3 torque converter?
Our stage 3 single disc billet converters are designed for those who have lightly modified engines or for those that do not tow heavy weights. The showpiece of our converters is our PATENTED torque converter stator sprag retainer.
What are the three main components of a torque converter?
In a torque converter there are at least three rotating elements: the impeller, which is mechanically driven by the prime mover; the turbine, which drives the load; and the stator, which is interposed between the impeller and turbine so that it can alter oil flow returning from the turbine to the impeller.
