Lock-up Mechanism
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2014 Honda Ridgeline, 2013 Honda Ridgeline, 2012 Honda Ridgeline, 2011 Honda Ridgeline, and 2010 Honda Ridgeline. However, it is still accessible from the selected car via links, so may be relevant.
The lock-up mechanism causes the input shaft (mainshaft) to rotate at the same speed as the engine crankshaft. Pressurized ATF is drained from between the torque converter cover and the torque converter clutch piston through a fluid passage, causing the torque converter clutch piston to be held against the torque converter housing. Together with the hydraulic control, the PCM optimizes the timing and degree of lock-up. The lock-up mechanism operates in D (2nd, 3rd, 4th, and 5th gears) and D3 driving mode (2nd and 3rd gears).