Lock-Up System
Lock-up SystemThe lock-up mechanism of the torque converter clutch operates in D position (2nd, 3rd, 4th and 5th), in D3 position (2nd and 3rd), and M (manual mode) position (3rd, 4th and 5th). The pressurized fluid is drained from the back of the torque converter through a fluid passage, causing the torque converter clutch piston to be held against the torque converter cover. As this takes place, the mainshaft rotates at the same speed as the engine crankshaft. Together with the hydraulic control, the PCM optimizes the timing and volume of the lock-up mechanism. When the shift solenoid valve E is turned on by the PCM, shift solenoid valve E pressure switches the lock-up shift valve lock-up on and off. The A/T clutch pressure control solenoid valve A and the lock-up control valve control the volume of the lock-up conditions.
Torque Converter Clutch Lock-up ON (Engaging Torque Converter Clutch)
Fluid in the chamber between the torque converter cover and the torque converter clutch piston is drained off, and fluid entered from the chamber between the pump and stator exerts pressure through the torque converter clutch piston against the torque converter cover. The torque converter clutch piston engages with the torque converter cover; the torque converter clutch lock-up is ON, and the mainshaft rotates at the same speed as the engine.
Torque Converter Clutch Lock-up OFF (Disengaging Torque Converter Clutch)
Fluid entered from the chamber between the torque converter cover and the torque converter clutch piston passes through the torque converter and goes out from the chambers between the turbine and the stator, and between the pump and the stator. As a result, the torque converter clutch piston moves away from the torque converter, and the torque converter clutch lock-up is released; torque converter clutch lock-up is OFF.
No Lock-up
Shift solenoid valve E is turned OFF by the PCM, and shift solenoid valve E pressure (SE) is not applied to the lock-up shift valve. The lock-up shift valve stays in the right side to uncover the ports of torque converter pressure leading to the left side of the torque converter and releasing from the right side of the torque converter. Torque converter pressure (92) changes to (94) at the lock-up shift valve, and enters into the left side of the torque converter to disengage the torque converter clutch. The torque converter clutch piston keeps away from the torque converter cover, the torque converter clutch lock-up is OFF.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Partial Lock-up
As the speed of the vehicle reaches the prescribed value, shift solenoid valve E is turned ON by the PCM, and shift solenoid valve E pressure (SE) is applied to the right side of the lock-up shift valve. The lock-up shift valve is moved to the left side to switch the port of torque converter pressure (91) leading to the right side of the torque converter, and the port of torque converter pressure (94) releasing from the left side of the torque converter. Torque converter pressure (91) flows to the right side of the torque converter to engage the torque converter clutch. The PCM also controls the A/T clutch pressure control solenoid valve A to regulate A/T clutch pressure control solenoid valve A pressure (55) applying to the lock-up shift valve and lock-up control valve. The position of the lock-up control valve depends on A/T clutch pressure control solenoid valve A pressure (55) and torque converter pressure released from the torque converter. The lock-up control valve controls volume of the torque converter clutch lock-up conditions until fluid between the clutch piston and torque converter cover is released fully; the torque converter clutch partial lock-up condition.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Full Lock-up
When the vehicle speed further increased, the PCM controls the A/T clutch pressure control solenoid valve A to increase A/T clutch pressure control solenoid valve A pressure (55), and the lock-up control valve is moved to the left by pressure increased amount. Torque converter pressure (94) from the left side of the torque converter is released fully at the lock-up control valve, and torque converter pressure (91) engages the torque converter clutch securely; the torque converter clutch full lock-up condition.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Shift Lever Mechanism
The shift lever has five positions; P, R, N, D, and D3 positions. D position has two modes; automatic shift mode and sequential sportshift mode with the shift lever moved to M position. The shift lever shifts along with the A/T gear position indicator panel. The shift lever can be shifted out of P position and into R position without pressing the shift lever. The shift lock/reverse lock mechanism is an additional shift lever lockout mechanism.
The shift lever is engaged with the shift lever link in P, R, N, D, and D3 positions. This unit shifts the transmission using the shift cable connected between the shift cable link and the transmission control shaft.
In the M position, the shift lever is disengaged from the shift lever link, and the shift lever can be used to shift gears manually between 1st through 5th, much like a manual transmission.
Shift Lever Mechanism in M Position
When the shift lever shifts to the M position, the shift lever is disengaged from the shift lever link/shift lever pivot, and the shift lever link lock pops up to engage with the shift lever bracket base; the shift lever link/shift lever pivot and shifting position in the transmission are held in D position.
The shift lever link lock is spring loaded, it pops up in the M position, and does not engage the shift lever link/shift lever pivot in any position except M.
The shift lever fits into the M position by using a detent plunger with a spring. When shifting to upshift and downshift positions, the detent plunger is depressed by the detent bracket inner wall, and the detent plunger spring puts the shift lever back into the neutral position. The detent plunger also works in P position.
Shift Lock/Reverse Lock Mechanism
The shift lock system reduces the risk of the unintentional engine starting. Starting the engine is possible only in P and N positions. The shift lock mechanism consists of the shift lock solenoid, shift lock stop, shift lock release, and related parts. The reverse lock mechanism shares the shift lock mechanism. The shift lock solenoid is electronically controlled by the shift lock/reverse lock control system signals. If the shift lock solenoid does not operate, the shift lock/reverse lock mechanism can be released by pressing the shift lock release.
In P position while pressing the brake pedal, the shift lock solenoid is turned ON, and the shift lock solenoid plunger is retracted, releasing the shift lock stop. This allows the shift lever to be moved.
When the brake pedal is released, the shift lock solenoid remains OFF, and the shift lock stop locks the shift lever in P position.
When the shift lever is shifted to R position from N, the shift lock solenoid is turned ON, and the shift lock solenoid plunger is retracted to release the reverse lock stop. This allows the shift lever to be moved to R position.
If the allowable conditions (acceleration at 6 mph (10 km/h) or less, and deceleration at 5 mph (8 km/h) or less in D position) for turning ON the solenoid are not met, the shift lock solenoid remains OFF, and the reverse lock stop locks the shift lever in N position.