A/T System Description - Hydraulic Controls

A/T System Description - Hydraulic Controls

Hydraulic Controls

Valve Bodies

The valve body includes the main valve body, the regulator valve body, and the servo body. The ATF pump is driven by splines on the end of the torque converter which is attached to the engine. Fluid flows through the regulator valve to maintain specified pressure through the main valve body to the manual valve, directing pressure to the shift valves and to each of the clutches via the shift solenoid valves. Shift solenoid valves A, B, C, D, and E are bolted on the servo body. A/T clutch pressure control solenoid valves A, B, and C are mounted on the outside of the transmission housing.






Hydraulic Controls (cont'd)

Main Valve Body

The main valve body contains the manual valve, shift valves A, B, C, and E, the relief valve, the lock-up control valve, the cooler check valve, the servo control valve, the ATF pump drive gear, and the ATF pump driven gear. The primary function of the main valve body is to switch hydraulic fluid pressure on and off and to the hydraulic control system.






Regulator Valve Body

The regulator valve body contains the regulator valve, the torque converter check valve, the lock-up shift valve, and the 1st and 3rd accumulators.






Regulator Valve

The regulator valve maintains constant hydraulic pressure from the ATF pump to the hydraulic control system, while also providing fluid to the lubrication system and the torque converter. The fluid from the ATF pump flows through B and C. Fluid entering from B flows through the valve orifice to the A cavity. This pressure in the A cavity pushes the regulator valve toward the valve spring side, and this movement of the regulator valve uncovers the fluid port to the torque converter and the relief valve. The fluid flows out to the torque converter and the relief valve, and the regulator valve returns under spring force. According to the level of the hydraulic pressure through B, the position of the regulator valve changes, and the amount of fluid from C through torque converter also changes. This operation is continuous, maintaining the line pressure.





Increases in hydraulic pressure according to torque are regulated by the regulator valve using stator torque reaction. The stator shaft is splined with the stator in the torque converter, and the stator shaft arm end contacts the regulator spring cap. When the vehicle is accelerating or climbing (torque converter range), stator torque reaction occurs on the stator shaft, and the stator shaft arm end pushes the regulator spring cap in the direction of the arrow in proportion to the reaction. The stator reaction spring compresses, and causes the regulator valve to increase the line pressure which is regulated by the regulator valve. The line pressure reaches its maximum pressure when the stator torque reaction reaches its maximum travel.






Hydraulic Controls (cont'd)

Servo Body

The servo body contains the servo valve, shift valve D, the accumulators for 2nd, 4th, and 5th, and shift solenoid valves A, B, C, D, and E.






Accumulator

The accumulators are located in the regulator valve body and the servo body. The regulator valve body contains the 1st and 3rd accumulators, and the servo body contains the 2nd, 4th, and 5th accumulators.