Hydraulic Control

HYDRAULIC CONTROL
The valve bodies include the main valve body, the secondary valve body, the regulator valve body, the servo body and the lock-up valve body. The ATF pump is driven by splines behind 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 each of the clutches.





Regulator Valve Body
The regulator valve body is located on the main valve body. The regulator valve body consists of the regulator valve, the torque converter check valve, the cooler check valve, and the lock-up control valve.





Lock-up Valve Body
The lock-up valve body with the lock-up shift valve and lock-up timing B valve is located on the regulator valve body.





Regulator Valve
The regulator valve maintains a constant hydraulic pressure from the ATF pump to the hydraulic control system, while also furnishing fluid to the lubricating system and torque converter.
Fluid flows through B and B'. The fluid enters through B and flows through the valve orifice to A, pushing the regulator valve to the right. According to the level of hydraulic pressure through B, the position of the valve changes, and the amount of the fluid through D from B thus changes. This operation is continued, maintaining the line pressure.

NOTE: When used, "left" or "right" indicates direction on the illustration below.





Stator Reaction Hydraulic Pressure Control
Hydraulic pressure increase, according to torque, is performed by the regulator valve using stator torque reaction. The stator shaft is splined to the stator and its arm end contacts the regulator spring cap. When the vehicle is accelerating or climbing (Torque Converter Range), stator torque reaction acts on the stator shaft and the stator shaft arm pushes the regulator spring cap in the direction of the arrow in proportion to the reaction. The spring compresses and the regulator valve moves to increase the regulated control pressure or line pressure. Line pressure is maximum when the stator reaction is maximum.





Main Valve Body
The main valve body houses the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 4th exhaust valve, the CPC valve, and the relief valve. The primary functions of this valve body are switching ATF passages on and off, and controlling the hydraulic pressure going to the hydraulic control system.





Secondary Valve Body
The secondary valve body is located on the main valve body. The secondary valve body houses the 3-2 kick-down valve, the 4-3 kick-down valve, the 2-3 orifice control valve, the orifice control valve, the 3-4 shift valve, the modulator valve, and the servo control valve.





Servo Body
The servo body is located on the secondary valve body. The servo body houses the servo valve (integrated with the shift fork shaft), the throttle valve B, and the accumulator pistons.





Accumulator Pistons
The accumulator pistons are assembled in the servo body and right side cover. The 1st-hold clutch accumulator piston is in the right side cover, and the 1st, 2nd, 3rd, and 4th accumulator pistons are in the servo body.