Automatic Transmission/Transaxle: Description and Operation

Fig. 1 Wiring Diagram Of Mitsubishi Charging System:

These transmissions, Fig. 1, combine a torque converter with a fully automatic three speed gear system. The converter housing and transmission case are an integral aluminum casting. The transmission consists of two multiple disc clutches, an overrunning (one-way) clutch, two servos and bands and two planetary gear sets to provide three forward speeds and reverse.
The common sun gear of the planetary gear sets is connected to the front clutch by a driving shell that is splined to the sun gear and to the front clutch retainer.
The hydraulic system consists of a single oil pump and a valve body that contains all the valves except the governor valve.
Venting of the transmission is accomplished by a drilled passage through the upper part of the front pump housing.
The torque converter is attached to the engine crankshaft through a flexible driving plate, and is cooled by circulating the transmission fluid through an oil-to-water type cooler located in the radiator lower tank. A lock-up feature is used on most applications.
The lock-up converter system consists of a lock-up mechanism within the converter, and a lock-up module and switch valve attached to the valve body. The internal lock-up mechanism consists of a sliding clutch piston, torsion springs and clutch friction material. The friction material is attached to the front cover, the clutch piston is mounted in the turbine, and the torsion springs are located on the forward side of the turbine. The torsion springs are used to dampen out engine firing impulses, while absorbing the shock loads that occur during lock-up.
When the transmission reaches a predetermined speed, transmission fluid is channeled through the input shaft and into the area between the clutch piston and turbine. The fluid pressure forces the piston against the front cover friction material, locking the turbine to the impeller. When vehicle speed decreases, or the transmission shifts out of direct drive, fluid pressure is released, the clutch piston retracts, and the converter operates in a conventional manner.
Because the lock-up mechanism is completely enclosed within the converter, lock-up converters have a circular decal attached to the front cover stating the converter type and stall ratio.
Do not attempt to interchange conventional and lock-up convertors. The transmission input shaft and valve body used for lock-up operation are different.