SPACER 2088575 - Caterpillar

Description of Components
The lockup clutch in the torque converter improves the efficiency of the power train during periods of sustained operation in one direction. An example is load and carry operations. The torque converter is in direct drive with the engine when the lockup clutch is engaged. Slippage in the torque converter is eliminated and efficiency is improved.The impeller and the turbine are still rotating in oil when the lockup clutch is engaged. This results in heat generation and power loss in the torque converter. The heat that is generated and the engine power that is required in order to turn the turbine and the impeller can be reduced in most torque converters by adding a one-way clutch to the stator in the torque converter. This sprag clutch allows the stator to rotate when the lockup clutch is engaged. This will improve efficiency. This will also reduce heat that is generated in the torque converter.Recommended Operating Techniques
The lockup clutch will not provide any benefits during operations that involve frequent directional changes. The lockup clutch will not provide any benefits if the lockup clutch is only engaged for short periods of time. The torque converter will be locked and unlocked several times if the lockup clutch is enabled during operations that involve a large number of directional changes. This will reduce the service life of the torque converter. The lockup clutch should be disabled during operations that involve a large number of directional changes. One example is loading a truck.The lockup clutch should be disabled during operations that involve sudden deceleration. One example is driving into a pile. Large torque spikes will result if the lockup clutch is engaged and the machine is suddenly decelerated. This will lead to premature failure of components.The lockup clutch should also be disabled during operations that involve a sudden increase in loads to the power train. The output speed of the torque converter will rapidly drop when the lockup clutch is suddenly disengaged and the power train is under a high load. The sudden change will cause the stator clutch to lockup suddenly. This will cause high impact loads to the stator clutch. Repetitive impact loading will result in premature failure of the stator clutch.When you are digging, the lockup clutch should be disabled before the bucket contacts the material. The lockup clutch can be disabled by placing the lockup clutch switch into the OFF position. The lockup clutch will also disengage if the output speed of the torque converter falls below the engagement speed of the lockup clutch. The disengagement speeds of the torque converters are listed in Table 1. When the lockup clutch is engaged, the output speed of the torque converter will match the engine speed.Reference: Refer to the Operation and Maintenance Manual, "Torque Converter Lockup Control" for more information on the switch location.The lockup clutch can also be disabled by using the following methods for some of the machines.
The lockup clutch is disabled for two seconds after a downshift