The torque converter housing is filled with fluid by the transmission pump. The impeller is the driving member with its curved vanes picking up fluid in the converter housing and directing it toward the turbine.
The turbine is the driven member, having vanes that receive fluid from the rotating impeller.
With sufficient fluid flow from the impeller, the turbine rotates to turn the transmission input shaft.
The stator is the reaction member whose curved vanes multiply the fluid force being sentback to the impeller by the turbine.
The impeller is attached to the crankcase via a flexplate or flywheel, and the turbine is attached to the front of the transmission input shaft.
Fluid is pumped into the torque converter housing by the transmission pump. As the impeller is turned by the engine, its vanes pick up fluid in the housing and throw the fluid outward toward the turbine.
As the fluid moves, it follows two flow paths:
• Rotary flow: The oil flow path, in a torque converter, that is in the same circular direction as the rotation of the impeller (engine crankshaft rotation).
• Vortex flow: The oil flow path, in a torque converter, that is at a right angle to the rotation of the impeller and to rotary flow.
Three elements of a torque converter are curved backward to boost the acceleration of the oil flow as fluid leaves the impeller. The turbine vanes are curved on their inlet sides, back toward the impeller to absorb as much energy as possible from fluid moving through the turbine.
Turbine vanes also curve to absorb shock and a loss of power whenever there is a sudden change in oil flow between the impeller and the turbine.
Turbine vanes are curved to take advantage of the basic hydraulic principle that the more the direction of a moving fluid is diverted, the greater the force exerted by the fluid on the diverting surface.
Stator vanes curve in the opposite direction from impeller and turbine vanes. Since the stator is located between the impeller and the turbine, its curved vanes multiply the force returning to the impeller from the turbine.
Fluid that leaves a moving impeller to enter a turbine does not exit as rotary flow or vortex flow. It exits as a combination of both. Fluid from the impeller strikes the vanes of the turbine. When the speed and force of the fluid hitting the turbine vanes is great enough, the turbine rotates.
Rotary flow and vortex flow moving through the turbine vanes at the same time create resultant force, which is the combined force and flow direction in the torque converter.
The stator is the reaction member whose curved vanes multiply fluid force being sent back to the impeller by the turbine. The stator is mounted on a one-way overrunning clutch that is splined to a stationary extension of the oil pump assembly. This extension is called the reaction shaft or stator support.
The hub at the rear of the torque converter housing, which is the back of the impeller passes over the stator support and through the front seal into the oil pump. The converter engages the drive gear or rotor of the pump to drive it. Because the converter hub is part of the housing that is bolted to the engine, the oil pump is turning and pumping fluid whenever the engine is running.
Because of the complexity of fluid flow through the converter, there is a great deal of stress on the fluid in the automatic transmission. The converter serves as a direct link between the engine and drive wheels of the vehicle.
Typically, the converter has no means of draining the fluid it contains, which is why less than 50 percent of the transmission fluid is changed during a conventional drain and refill service.
Valve Body
The valve body is where many of the hydraulic valves are housed. This is where fluid is channeled and directed throughout the transmission to determine when shifting of gear ratios occurs. This is accomplished in relation to engine load and throttle position.