Torque Converter: Description and Operation

Transmission Torque Converter

Operation

The Transmission Control Module (TCM) is able to monitor the state of the torque converter clutch at all times.
There are three operating modes for the converter
1. Fully open - Torque converter 'unlocked'
2. Fully closed - Torque converter 'locked'
3. Slip control - The TCM monitors slip and may apply sufficient pressure to allow a small degree of slip. This mode maximizes economy by reducing slip to a minimum whilst providing isolation from drive-line shunt and vibration.
The TCM constantly measures the slip within the torque converter by comparing engine speed (via CAN) and input (turbine speed). Differences in these speeds indicate the amount of slip.