In a lock-up converter, the impeller and turbine are locked together when conditions are suitable, to provide a 1 to 1 drive from the engine to the transmission input shaft.
Lock-up normally occurs at higher road speeds when light throttle openings are being used.
The lock-up piston engages in slots in the turbine and can move axially, for engagement, and disengagement.
Torsional damper springs are built into the turbine/ piston assembly. When the clutch is engaged, these springs dampen drive-line, and torsional vibrations.
When the clutch facing on the piston comes in contact with the internal machined surface on the wall of the converter housing, lock-up occurs.
This provides a 1 to 1 connection from engine to transmission, with no slippage between components.
