Car Forum World

i have a lexus and on the specifications. and information it says electronically controlled transmission.and its an auto

Older Transmissions were constructed to shift with Oil pressure. They didn't shift smoothly and on occasion caused by wear they could not shift at all.

The newer transmissions are conrolled by the "On Board" computer. they're set to shift as indicated by the speed of the drive shaft. Some cars have two speed switches that work off of the rear of the Transmission. Some cars only have one. there's more than one item that controls the speed at which the auto will shift.

Electrically controlled changing is smoother and less trouble some than the older technique.

electro transmission

the computer monitors transmission conditions, acceleration pedal inputs etc and changes the transmission shift points to get you best performance and economy

Older transmissions used to be used to be controlled by vacuum coming from the engine. It told the transmission when to shift by the amount of vacuum which changed by the revolutions of the engine. More revolutions meant more vacuum. These days, the computer reads to revolutions and acceleration of the engine. It, in turn, tells the transmission when to shift depending on demand and RPMs of the engine.

Well you got a lot of it but here are a couple additions. Older transmissions used a mix of vacuum and hydraulic pressures. This could in turn use the oil in the tranny to push on certain pistons at certain times. This could make for rough changing and on occasion no changing. The electronically controlled transmission uses a computer to do the changing through the use of solenoids. The computer does this with the inputs from different sensors such as: Speed sensor, Throttle position sensor, Manifold pressure sensor, and others that I can not think of now. complex indeed.

On earlier auto transmission, the auto feature is controlled by a group of valves working together to control the changing sequences.
electronically controlled transmission as the name implies,,it is controlled electronically by a computer. instead of using the old valves from old transmission they use electronic softwares to control changing sequences. some of the added parts are speed sensors, solenoid valves and control unit which is the memory.

some benefits of electronic transmission are the following,
lesser in volume,lighter in weight
easy to preserve and fix,, most parts are available externally
smooth in shift and quicker in reaction