Lock-Up System
Lock-up SystemThe lock-up mechanism of the torque converter clutch operates in D position (2nd, 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 torque converter clutch solenoid valve activates, modulator pressure changes to switch lock-up on and off. The lock-up control valve and the lock-up timing valve control the amount of lock-up conditions according to AM clutch pressure control solenoid valve C.
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 entering 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 through 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 lock-up clutch is released; torque converter clutch lock-up is OFF.
No Lock-up
The torque converter clutch solenoid valve is turned OFF by the PCM. The lock-up shift valve receives LC pressure (LA) on the left side, and modulator pressure (6) on the right side. The lock-up shift valve is in the right side to uncover the port leading torque converter pressure (92) to the left side of the torque converter. Torque converter pressure (92) becomes torque converter pressure (94), and enters into the left side of the torque converter to disengage the torque converter clutch. The 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, the torque converter clutch solenoid valve is turned ON by the PCM to release LC pressure (LA) in the left cavity of the lock-up shift valve. Modulator pressure (6) is applied to the right side of the lock-up shift valve, then the lock-up shift valve is moved in the left side to switch the port leading torque converter pressure to the right side of the torque converter. Torque converter pressure (91) is applied to the right side of the torque converter to engage the torque converter clutch. The PCM also controls A/T clutch pressure control solenoid valve C, and LS C pressure (58) is applied to the lock-up control valve and the lock-up timing valve. When LS C pressure (58) is lower, torque converter pressure (91) from the lock-up timing valve is lower. The torque converter clutch is engaged partially. LS C pressure (58) increases, and the lock-up timing valve is moved to the left side to uncover the port leading torque converter pressure to high. The torque converter clutch is then engaged securely. Under this condition, the torque converter clutch is engaged by pressure from the right side of the torque converter; this lock-up condition is in partial lock-up.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Full Lock-up
When the vehicle speed increases, the PCM sends a signal to the A/T clutch pressure control solenoid valve C to increase LS C pressure (58). The LS C pressure (58) is applied to the lock-up control valve and the lock-up timing valve, and moves them to the left side. Under this condition, torque converter back pressure (F2) is released fully, causing the torque converter clutch to be fully engaged.
NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.
Shift Lever Mechanism
The shift lever has five positions; the P, R, N, D, and L positions. The D position has two modes; automatic shift mode and sequential sportshift mode with the shift lever moved to the M position. The shift lever movement and position is indicated by the A/T gear position indicator panel. The shift lever can be shifted out of the P position and into the 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 the P, R, N, D, and L 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 the 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 detent plunger spring puts the shift lever back into the neutral position. The detent plunger also works in the 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 the P and N positions. The shift lock mechanism consists of the shift lock solenoid, shift lock stop/reverse 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 the P position while pressing the brake pedal and releasing the accelerator, 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 or the accelerator is pressed, the shift lock solenoid stays OFF, and the shift lock stop locks the shift lever in the P position.
When the shift lever is shifted to the R position from the 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 the R position.
If the conditions (acceleration at 6 mph (10 km/h) or less, and deceleration at 5 mph (8 km/h) or less in the D position) for turning ON the solenoid are not met, the shift lock solenoid stays OFF, and the reverse lock stop locks the shift lever in the N position.