Valve Body - Operation

OPERATION



















CAUTION: The Transmission Control Module (TCM), or Transmission Control Module Assembly (TCMA) is extremely sensitive to Electrostatic Discharge (ESD). Always use a ground strap and follow the ESD guidelines in ELECTROSTATIC DISCHARGE (ESD) SENSITIVE DEVICES . Failure to follow these instructions may result in damage to the TCM/TCMA.

The valve body, which includes the Transmission Control Module (TCM), controls the delivery and pressure of transmission fluid. The TCM is integrated into the valve body. The TCM regulates the amount of hydraulic pressure used to engage the clutches and the Torque Converter Clutch (TCC), in addition to directing hydraulic pressure to engage or release any given clutch for any given required gear. The TCM will actuate the valves via solenoids based on the position of the shifter, transmission fluid temperature, engine operating conditions, traction conditions and driver demands. During a shift, the TCM will actuate the solenoids to match the gear ranges to the optimal torque range of the engine based on the position of the accelerator pedal, shifter and vehicle speed as determined by the PCM based on input from the Vehicle Speed Sensor (VSS) and ABS module. Due to the complexity of the 8HP45 transmission control system, always refer to the transmission electrical/electronic diagnostics when attempting to diagnose transmission problems.

If the Transmission Control Module Assembly (TCMA) is replaced, it must be programmed and a drive learn needs to be performed before returning the vehicle to the customer. for programming and drive learn procedures. 8HP45 TCM Programming Procedure