Functional Description - Torque Converter
DESCRIPTION
| 1 - Turbine | 4 - Input Shaft |
| 2 - Impeller | 5 - Stator Shaft |
| 3 - Stator | 6 - Turbine Damper |
The torque converter must be replaced if a transmission failure resulted in large amounts of metal or fiber contamination in the fluid.
The torque converter is a hydraulic device that couples the engine crankshaft to the transmission. The torque converter is a sealed, welded unit that is not repairable and is serviced as an assembly. The torque converter consists of an outer shell with an internal turbine, a stator, an overrunning clutch, an impeller (2), and an electronically applied converter clutch. The converter clutch provides reduced engine speed and greater fuel economy when engaged. Clutch engagement also provides reduced transmission fluid temperatures. The Torque Converter Clutch (TCC) activates in third through fifth gears.
A turbine damper has been added for some applications to help improve vehicle Noise, Vibration, and Harshness (NVH) characteristics.
OPERATION
| 1 - Turbine | 7 - Cover Shell |
| 2 - Impeller | 8 - Internally Toothed Disc Carrier |
| 3 - Stator | 9 - Clutch Plate Set |
| 4 - Input Shaft | 10 - Externally Toothed Disc Carrier |
| 5 - Stator Shaft | 11 - Turbine Damper |
| 6 - Piston |
The torque converter housing has a unique shape to incorporate the TCC and flex plate connection. The torque converter uses the typical turbine, impeller and stator assemblies found in a standard torque converter assembly. The torque converter drives the pump through the splines on the inside of the hub. The torque converter uses a multi-disc torque converter clutch system that improves the durability and the holding pressure in the lock-up circuit. The torque converter incorporates a turbine dampening system. This system suppresses torsional vibrations from the engine to ensure optimal shift quality and reduce noise and vibration concerns.
TCC RELEASE - When the TCC is open, the TCC piston is pushed to its default position by torque converter chamber pressure. The Torque Converter Switch Valve (SV-TC) provides pressure for torque converter operation which has been regulated by the Torque Converter Pressure Regulating Valve (TC-V). After exiting the torque converter, fluid moves into the cooling and lubrication circuits. The converter pressure retention valve (TCH1-V) ensures the torque converter pressure is a minimum of 0.35 bar (5 psi) when the TCC is open.
TCC APPLY - When the TCC solenoid is energized, fluid is directed to the torque converter switch valve (SV-TC) and TCC lockup valve (TCC-V). The TCC lockup valve directs fluid to the TCC and torque converter chamber. The torque converter switch valve directs fluid exiting the converter chamber to a secondary pressure retention valve (TCH2-V) which is calibrated to retain 1.0 bar (14.5 psi) of pressure in the converter. The torque converter switch valve also directs line pressure to the cooler and lubrication circuit.