RE4RO3A Transmission |
Source: scottmeister at Patrol4x4.com
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It also modulates the hydraulic pressure supplied to the clutch packs through pulse width modulation (PWM) of the line pressure solenoid, and applies torque converter lock-up based on various criteria (shifter selection, vehicle speed and TPS position, namely). The figure below illustrates the basics of the control system.
• Torque converter clutch solenoid valve. This clutch locks the turbine and impeller of the torque converter together;
• Shift solenoid valve A and B. These determine which gear is selected by altering the route of hydraulic pressure through the valvebody;
• Overrun clutch solenoid, which allows engine braking to occur by locking the front planetary carrier with the rear internal gear; and the
• Line pressure solenoid, which through the dropping resistor, is pulse width modulated to determine the pressure generated by the oil pump. Minimising the pressure generated at light loads reduces the pumping losses incurred by the transmission.
When in ‘D’ mode, the selected gear is determined based on the activation of the two shift solenoids by the TCU. The solenoids, located on the valvebody, determine to which locations the hydraulic pressure is supplied.
• 1st gear = Shift solenoid A and B active;
• 2nd gear = Shift solenoid B only active;
• 3rd gear = Shift solenoid A and B inactive; and
• 4th gear = Shift solenoid A only active.
The TCU will also activate the overrun clutch and torque converter lockup as necessary. For all gear shifter positions (which controls the "manual valve" in the valvebody), the valvebody has different circuits to alter slightly how the transmission operates. These functions are seen in the figure below.
There should be a metal tag attached to the transmission which will tell you the serial number and transmission code. The table below shows a selection of transmission codes and a corresponding selection of information I have gleaned from several different FSMs.
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