Automatic transmissions are most definitely the most common installed drive-train option on modern vehicles. Unfortunately this convenient automatic shifting option is sometimes accompanied with problems that can be expensive to repair.

Automatic transmission operation

This type of transmission does not need a clutch pedal and shifts through the forward gears without control from the driver all by itself when the drive range is selected.

Instead of a clutch and pressure plate to connect the engine to the rear wheels the automatic transmission uses a torque converter which is a fluid coupling to transfer this power from the engine’s flywheel to the transmission input shaft and back to the wheels.


The torque converter allows for proper engine idle without moving the vehicle and smooth transfer of power at all engine speeds. On vehicles of the last 20 years the shifting is controlled by both electrical and hydraulic principles working together.

The hydraulic part of the equation is an intricate network of passageways, fluid controlled pistons and servos plus other components that use the magic of hydraulic oil pressure to control the internal operation.

The electrical part of the equation is usually the solenoids and electrically controlled valves that open and close to allow hydraulic fluid pressure to flow in the desired direction and accomplish a specific task.

On modern vehicles the main computer is what controls the operation of the electrical circuits. The computer uses its varied inputs from sensors such as vehicle speed and throttle position to determine what actions are necessary for the transmission to apply.

As an example a solenoid valve can open to let hydraulic fluid flow to apply a certain gear set to perform a specific action. These gear sets provide many foreword speeds as well as reverse.

Please note that there is a minimum $59.17 (plus ss & tx) vehicle diagnosis charge for vehicles that do not complete repairs with our facility.

Thank you for your understanding.

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