Torque Converter Use And Failures.
In short, it is the union between the engine and the automatic transmission. In automatic vehicles there is no clutch pedal, it is not necessary because the power from the engine to the automatic transmission is transferred through oil, avoiding metals to touch and letting the engine and the transmission to rotate at different speeds.
It is used in Automatic transmissions on automobiles, buses, and on/off highway trucks, forwarders and other heavy duty vehicles, marine propulsion systems and industrial power transmission such as conveyor drives, almost all modern forklifts, drilling rigs, construction equipment, winches, and railway locomotives.
Allison is the world’s largest automatic transmission manufacturer for automatic and hybrid transmissions for commercial use, so Allison is the world’s largest torque converter manufacturer.
Main problems with torque converter.
Overheating: If there is too much work or energy needed to move the vehicle or machinery, this means that the engine is rotating fast and the automatic transmission is not moving. This is slippage, and may overwhelm the Allison torque converter’s ability to dissipate heat. This could result in damage to the elastomer seals that retain fluid inside the converter, causing leaking and eventually will stop functioning due to lack of fluid.
Stator clutch seizure: The inner and outer elements of the one-way stator clutch become locked together, preventing the stator from rotating during the coupling phase. The efficiency of a converter with a seized stator clutch will be very poor in the coupling phase. Under such conditions will usually occur Allison torque converter parts overheating if continued operation is attempted.
Stator clutch breakage: If stator clutch brakes, the stator will freely counter-rotate in the direction opposite to that of the pump sending no power to the transmission. This can happen if A very abrupt application of power is applied and can cause shock loading of the stator clutch, resulting in breakage.
Blade deformation and fragmentation: Pump and/or turbine blades may be deformed if they are subjected to abrupt loading or excessive heating of the converter, they may be separated from their hubs and/or annular rings, or break up into fragments. In extreme cases, the converter can be destroyed.
Ballooning: Is the deformation of the torque converter housing caused by excessive loading, or operating a torque converter at very high RPM due to internal pressure and/or the stress imposed by inertia. Ballooning can cause the converter housing to rupture, resulting in the violent dispersal of metal fragments and hot oil all over a wide area.
How to fix those problems
Because the Alison torque converter is sealed, it is difficult to prevent any problem. Once it is broken, it can be replaced with a new one or it is possible to buy the parts and fix it or buy one that has been rebuilt.
Is it worth fixing it instead of buying a new one?
Usually rebuilt Allison torque converters are cheaper than the new ones and they have a really good quality, lasting as long as a new one.