Lock-up Mechanism
WARNING: This page is about a different car, the 2011 Acura TL, 2010 Acura TL, and 2009 Acura TL. 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 S (2nd, 3rd, and 4th gears)