System Components

GENERAL
The automatic transmission is a combination of a 3-element torque converter and triple-shaft automatic transmission which provides 4 speeds forward and 1 reverse. The entire unit is positioned in line with the engine.

TORQUE CONVERTER, GEARS AND CLUTCHES
The torque converter consists of a pump, turbine and stator,assembled in a single unit. The torque converter is connected to the engine crankshaft so they turn together as a unit as the engine turns. Around the outside of the torque converter is a ring gear which meshes with the starter pinion when the engine is being started. The entire torque converter assembly serves as a flywheel while transmitting power to the transmission mainshaft. The transmission has three parallel shafts, the mainshaft, the countershaft and the sub-shaft. The mainshaft is in line with the engine crankshaft. The mainshaft includes the 1st, and 2nd/4th clutches, and gears for 3rd, 2nd, 4th, reverse and 1st (3rd gear is integral with the mainshaft, while reverse gear is integral with the 4th gear). The countershaft includes the 3rd clutch and gears for 3rd, 2nd, 4th, reverse, 1st and parking. Reverse and 4th gears can be locked to the countershaft at its center, providing 4th gear or reverse, depending on which way the selector is moved. The sub-shaft includes the 1st-hold clutch and gears for 1st and 4th. The gears on the mainshaft are in constant mesh with those on the countershaft and sub-shaft. When certain combinations of gears in the transmission are engaged by the clutches, power is transmitted from the mainshaft to the countershaft to provide D4, D3, 2, 1, and R.

HYDRAULIC CONTROL
The valve body assembly includes the main valve body, the secondary valve body, the regulator valve body, the servo body, the modulator valve body, the lock-up valve body, and the governor body, through the respective separator plates. They are bolted on the torque converter housing. The main valve body contains the manual valve, the 1-2 ship valve, the 2-3 shin valve, the 3-4 shim valve, the 3-2 timing valve, the 4th exhaust valve, the relief valve, and the ATF pump gears. The secondary valve body contains the 4-3 kick-down valve, the 2nd ON orifice control valve, the 2-3 orifice control valve, the 2-1 timing valve, the Clutch Pressure Control (CPC) valve, the servo control valve, the reverse control valve, and the governor cut valve. The regulator valve body contains the pressure regulator valve, the lock-up control valve, the torque converter check valve, and the cooler check valve. The servo body contains the servo valve which is integrated with the reverse shin fork, the throttle valves A and B. the 2/3 4 orifice control valve, and the accumulators. The modulator valve body, which is bolted on the servo body, contains the modulator valve. The lock-up valve body contains the lock-up ship valve and the lock-up timing B valve, and is bolted on the regulator valve body. The governor body is bolted on the torque converter housing near the differential assembly. Fluid from the regulator passes through the manual valve to the various control valves.

LOCK-UP MECHANISM
In D4 position, 2nd, 3rd and 4th, and D3 position in 3rd, pressurized fluid is drained from the back of the torque converter through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the mainshaft rotates at the same speed as the engine crankshaft. Together with hydraulic control, the engine control module (ECM) optimizes the timing of the lock-up mechanism. The lock-up shift valve controls the range of lock-up according to the lock-up control solenoid valves A and B. and throttle valve B. The lock-up control solenoid valves A and B are mounted on the torque converter housing, and are controlled by the ECM.





GEAR SELECTION
The selector lever has seven positions; [P] PARK, [R] REVERSE, [N] NEUTRAL, [D4] 1st through 4th ranges, [D3] 1st through 3rd ranges, [2] 2nd gear and [1] 1st gear. Starting is possible only in P and N positions through the use of a slide-type, neutral-safety switch.

AUTOMATIC TRANSAXLE (A/T) GEAR POSITION INDICATOR
A/T Gear position indicator in the instrument panel shows what gear has been selected without having to look down at the console.