When you move the gear selector lever to the Overdrive (D) position from the Neutral (N) position, the following changes occur in order to shift the transmission into Overdrive Range -- First Gear.
In the Overdrive position, the manual valve directs line pressure into the drive fluid circuit. The manual valve blocks line pressure from entering the PRN fluid circuit and the manual valve opens the PRN fluid circuit in order to exhaust.
Low band fluid pressure exhausts from the servo, releasing the servo and the low and reverse band.
Drive fluid is orificed into the forward clutch fluid circuit. Forward clutch fluid pressure applies the forward clutch.
In first gear, the PCM energizes the 1-2 shift solenoid valve and the 1-2 signal fluid pressure acts on the 1-2 shift valve.
The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position against a spring force. Drive fluid is routed through the 1-2 shift valve.
Drive fluid is routed to the TFP Val. Position Sw. Assembly, which signals the PCM that the transmission is in the Overdrive range.
When you move the gear selector lever to the Overdrive (D) position from the Neutral (N) position, the following changes occur in order to shift the transmission into Overdrive Range -- First Gear.
Under certain conditions the hybrid vehicles engine will shut off and the electric auxiliary transmission fluid pump will start running to keep the transmission pressurized and ready for the engine restart. This engine off condition is a fuel economy feature and the L4 hybrid transmission's electric auxiliary fluid pump is an enabling component.
In the Overdrive position, the manual valve directs line pressure into the drive fluid circuit. The manual valve blocks line pressure from entering the PRN fluid circuit and the manual valve opens the PRN fluid circuit in order to exhaust.
Low band fluid pressure exhausts from the servo, releasing the servo and the low and reverse band.
Drive fluid is orificed into the forward clutch fluid circuit. Forward clutch fluid pressure applies the forward clutch.
In first gear, the PCM energizes the 1-2 shift solenoid valve and the 1-2 signal fluid pressure acts on the 1-2 shift valve.
The 1-2 signal fluid pressure keeps the 1-2 shift valve in the downshifted position against a spring force. Drive fluid is routed through the 1-2 shift valve.
Drive fluid is routed to the TFP Val. Position Sw. Assembly, which signals the PCM that the transmission is in the Overdrive range.