Is the transmission pump part of the torque converter?

No. In a conventional automatic transmission, the transmission’s hydraulic pump (often called the front or oil pump) is a separate component mounted in the transmission case. It is mechanically driven by the torque converter hub but is not part of the torque converter itself. The converter does contain an internal “pump” element called the impeller, which can cause confusion, but that impeller is different from the transmission’s hydraulic pump that supplies line pressure to the transmission.

How the torque converter and transmission pump relate

The torque converter and the transmission pump work together, but they are distinct parts with different jobs. The converter multiplies and transmits engine torque via fluid dynamics, while the transmission pump creates the hydraulic pressure that operates clutches, bands, valve bodies, lubrication circuits, and keeps the converter filled with fluid.

The torque converter’s major elements are commonly misunderstood, especially because one of its parts is called a “pump.” Here’s what’s inside a typical converter:

• Impeller (also called the pump of the converter): The input element welded to the converter cover that spins with the engine.
• Turbine: The output element connected to the transmission’s input shaft.
• Stator: Redirects fluid to improve torque multiplication, mounted on a one-way clutch.
• Lock-up clutch: Mechanically ties the converter to the engine at cruise to reduce slip and heat.

Together, these parts handle torque transfer and efficiency functions, but they do not generate system hydraulic pressure for the transmission—an external pump does that job.

The transmission’s hydraulic pump differs in construction and location from the converter’s internal elements:

• Location: Bolted to the front of the transmission case (behind the bell housing), not inside the converter.
• Drive method: Driven by the torque converter hub or tangs, which engage the pump’s inner gear or rotor when the engine runs.
• Pump types: Commonly crescent gear or gerotor; some modern units use variable-displacement vane pumps for efficiency.
• Purpose: Supplies line pressure for shifting, clutch actuation, lubrication, and converter fill and cooling.

This separation lets the transmission regulate hydraulic pressure independently while the converter manages torque transfer, even though both are mechanically linked at the front of the gearbox.

What actually drives the transmission pump

When the engine turns the torque converter, the converter hub engages the pump’s drive (via flats, notches, or tangs). As the hub spins, it turns the pump’s rotor or gear set, generating hydraulic pressure. If the engine is off, a traditional mechanical front pump can’t build pressure; this is why some modern vehicles add an auxiliary electric pump for stop-start functionality.

Modern variations and exceptions to know

While the basic answer remains “no, the pump isn’t part of the converter,” newer designs add nuances that can affect how pressure is maintained and how the vehicle behaves at idle or during stop-start events.

• Auxiliary electric pumps (start-stop): Many late-model automatics from Aisin, ZF, GM, and others add an electric pump to maintain pressure when the engine shuts off at lights.
• Hybrid transmissions: Often rely on electric pumps and may dispense with a traditional torque converter altogether, using motor-generators and clutches.
• Dual-clutch transmissions (DCTs): Typically use an external hydraulic unit or electrohydraulic module; they don’t have a torque converter in most applications.
• Continuously variable transmissions (CVTs): Use vane or gear pumps (mechanical and/or electric). Some have electric assist pumps for low-speed or start-stop operation.
• Variable-displacement pumps: Found in efficiency-focused automatics to reduce parasitic losses by adjusting output with demand.

Even with these advances, the hydraulic pump remains a transmission component, not a torque converter component, though the two are closely coupled through the converter hub.

Common symptoms: pump vs. torque converter issues

Diagnosing driveability complaints often involves telling pump-related pressure problems from converter-related torque transfer issues.

• Possible pump/pressure problems: Delayed engagement (especially cold), no movement in any gear, low/erratic line pressure readings, whining that changes with gear selection, overheating due to inadequate flow.
• Possible converter problems: Shudder during lock-up, excessive stall speed, poor acceleration off the line, overheating under load, metallic debris from clutch material if the lock-up clutch fails.
• Shared symptoms: Overheating and slipping can result from both, but pressure testing and scan data help pinpoint the source.

A hydraulic pressure test, fluid inspection, and converter lock-up command checks via scan tool are usually the fastest ways to separate pump faults from converter faults.

Maintenance and service notes

Sound maintenance reduces both pump and converter issues, especially in vehicles with towing or heavy-use duty cycles.

• Use the exact ATF specified by the manufacturer; friction and viscosity profiles matter for pressure control and lock-up behavior.
• Observe service intervals, including filter changes where applicable; some “sealed” units still have recommended service under severe duty.
• After transmission work, ensure the torque converter is fully seated on the pump drive tangs before installation to avoid pump damage.
• When hunting a shudder, consider updated fluid formulations or TSBs that address converter clutch friction characteristics.

Following OEM procedures and specs is critical; small deviations in fluid or assembly can cause pump cavitation, pressure loss, or premature converter clutch wear.

Bottom line

The transmission pump is not part of the torque converter. It lives in the transmission case and is driven by the converter hub to create the hydraulic pressure the transmission needs. The torque converter contains its own impeller (sometimes called a pump), but that’s a different component with a different function. Modern systems may add electric assist pumps, yet the pump remains a transmission component, separate from the converter.

Summary

No—the transmission’s hydraulic pump is separate from the torque converter, though it is driven by the converter hub. The converter manages torque transfer with its impeller, turbine, stator, and lock-up clutch, while the transmission pump supplies hydraulic pressure for shifting, lubrication, and converter flow. Modern automatics may add auxiliary electric pumps, but the pump is still a transmission component, not a converter part.

Is the transmission pump inside the torque converter?

A car’s transmission has a pump, which is located in the front of the transmission and is behind the torque converter, it sucks the transmission fluid from the sump and delivers it to all parts of the automatic transmission.

Which part of the torque converter is the driving part?

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 are the 4 parts of a torque converter?

The torque converter is what transmits that torque from the engine to a rotating driven load. In an automatic transmission car, the torque converter connects the power source to the load. Torque converters are comprised of five main components: the impeller, the turbine, the stator, a clutch, and the fluid.

What connects the torque converter to the transmission?

As it goes into the transmission. In order to give you an extra boost on acceleration from a stop and the third function is torque converter lockup which will lock the input.