Hydraulic Control

HYDRAULIC CONTROL
The hydraulic control system is controlled by the ATF pump, valves, and accumulators in the valve bodies. The ATF pump is driven by splines on the end of the torque converter which is attached to the engine. Fluid from the ATF pump 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. The valve body includes the main valve body, the secondary valve body, the ATF pump body, the regulator valve body, the throttle valve body, and the accumulator body. The throttle valve body is joined with the linear solenoid. The shift control solenoid valves A and B are bolted to the secondary valve body. The lock-up control solenoid valve assembly is bolted to the outside of the torque converter housing.

NOTE: The illustration shows'96 model;'97 -'98 models are similar.





Hydraulic Control/Lower Valve Body Assembly -'96 Model
The lower valve body assembly is located on the bottom of the transmission housing. The lower valve body assembly consists of the main valve body, the secondary valve body, and the ATF passage.

Main Valve Body
The main valve body houses the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the 4-3 kick-down valve, and the Clutch Pressure Control (CPC) valve. The primary functions of the main valve body are to switch fluid pressure on and off, and to control 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 modulator valve, the 3-4 orifice control valve, the 4-3 shift timing valve, the 1st accumulator piston, and the 2nd accumulator piston. The shift control solenoid valves A and B are bolted to the secondary valve body.

Throttle Valve Body/Linear Solenoid
The throttle valve body is joined with the linear solenoid, which is controlled by the PCM. The throttle valve body/linear solenoid assembly is located on the secondary valve body. The throttle valve body houses the throttle valve.





Hydraulic Control/Lower Valve Body Assembly - '97 - '98 Models
The lower valve body assembly is located on the bottom of the transmission housing. The lower valve body assembly consists of the main valve body, the secondary valve body, and the ATF passage.

Main Valve Body
The main valve body houses the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the 4-3 kick-down valve, and the main orifice control valve. The primary functions of the main valve body are to switch fluid pressure on and off, and to control 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 line pressure control valve, the modulator valve, the 3-4 orifice control valve, the 4-3 shift timing valve, the 1st accumulator piston, and the 2nd accumulator piston. The shift control solenoid valves A and B are bolted to the secondary valve body.

Throttle Valve Body/Linear Solenoid
The throttle valve body is joined with the linear solenoid, which is controlled by the PCM. The throttle valve body/linear solenoid assembly is located on the secondary valve body. The throttle valve body houses the throttle valve.





Hydraulic Control
ATF Pump Body
The ATF pump body is located on the torque converter housing. The ATF pump body consists of the ATF pump gears, the relief valve, the lock-up control valve, the lock-up timing valve, and the torque converter check valve. The torque converter check valve is located between the ATF pump body and the torque converter housing.

Accumulator Body
The accumulator body is located on the torque converter housing next to the ATF pump body. The accumulator body houses the 3rd accumulator piston and the 4th accumulator piston.

Regulator Valve Body
The regulator valve body is located on the ATF pump body. The regulator valve body consists of the regulator valve, the cooler relief valve, and the lock-up shift valve.

NOTE: The illustration shows'96 model; '97 -'98 models are similar.





Regulator Valve -'96 Model
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.

The fluid from the ATF pump flows through B and B'. The regulator valve has a valve orifice. The fluid entering from B flows through the orifice to the A cavity. This pressure of the A cavity pushes the regulator valve to the right 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 regulator valve moves to the left side.

According to the level of the hydraulic pressure through B, the position of the regulator valve changes and the amount of the fluid from B through D and C also changes. This operation is continued, maintaining the line pressure.

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





Regulator Valve -'97 -'98 Models
The regulator valve regulates line pressure, and also supplies fluid to the lubricating system and torque converter. To regulate line pressure, the regulator valve passes fluid from the ATF pump thorough the lubricating system and the torque converter. The regulator valve receives line pressure control pressure.

Fluid from the ATF pump flows through B and B'. Fluid entering from B flows through the regulator valve orifice to the A cavity. This pressure of the A cavity pushes the regulator valve to the right side. The line pressure control pressure flows to the right side of the regulator valve, and pushes the regulator valve to the left side. As a result, the regulator valve stays at a certain position to regulate line pressure. The line pressure control pressure increases according to the throttle opening (throttle B pressure), while line pressure increases according to line pressure control pressure.

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





Stator Reaction Hydraulic Pressure Control
Hydraulic pressure increase from torque is performed by the regulator valve using stator torque reaction. The stator shaft is splined with the stator in the torque converter, 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 arm pushes the regulator spring cap in the direction of the arrow in proportion to the reaction. The stator reaction spring compresses, and the regulator valve moves to increase the line pressure which is regulated by the regulator valve. The line pressure reaches its maximum when the stator torque reaction reaches its maximum.