High-quality torque converter shaft, part number 154-13-42521, suitable for bulldozer SD22.

High-quality torque converter shaft, part number 154-13-42521, for bulldozer SD22.

The term "torque converter shaft" isn't a very standard or single part name in automotive engineering, but it generally refers to the rotating shaft associated with a hydraulic torque converter. Understanding it requires considering the structure and working principle of the hydraulic torque converter.

Turbine Shaft:

Pump Impeller: Connected to the engine flywheel, driven by the engine to convert mechanical energy into the kinetic energy of the fluid (hydraulic oil).

Turbine: Rotates due to the impact of the hydraulic oil flow driven by the pump impeller, converting the kinetic energy of the fluid back into mechanical energy.

Steering Wheel: Located between the pump impeller and the turbine, it changes the direction of the oil flow, increasing torque (especially at lower speeds).

The turbine shaft is the output shaft connected to the center of the turbine. It transmits the rotational power of the turbine to the input shaft of the transmission. Therefore, "torque converter shaft" most often refers to this turbine output shaft, i.e., the output shaft of the torque converter, which directly drives the transmission. This is a key component for the torque converter's power output.

Input Shaft/Drive Shaft:

This shaft connects the engine's crankshaft (via the flywheel) to the torque converter's pump impeller. It is responsible for inputting power from the engine to the torque converter. Sometimes it may be broadly referred to as the "torque converter shaft" (referring to the input side), but less commonly as the "turbine shaft."

Torque Converter to Transmission Connection Shaft:

This is a broader concept, referring to the shaft located behind the torque converter housing, responsible for transmitting power from the torque converter (usually the turbine) to the gear set inside the transmission. Essentially, this is usually the turbine shaft (torque converter output shaft) mentioned above, which is also the transmission's input shaft. In automatic transmissions, the front end of this shaft is connected to the torque converter's turbine via splines or other means, while the rear end extends into the transmission.

Central Shaft/Support Shaft Inside the Torque Converter:

Inside the torque converter, the various impellers (pump impeller, turbine, guide impeller) need to rotate around a common central axis. There exists a central or hollow shaft that runs through or supports these components to ensure concentricity and transmit power (especially turbine power). This shaft is part of the torque converter's internal structure and is not usually referred to as the "torque converter shaft" alone, but it is the core of the entire rotating system.