Automatic transmission linear solenoids
Linear solenoids are electromechanical devices used in automatic transmissions (AT) to control the flow of hydraulic fluid to various transmission components. Their function is to change the direction and volume of fluid flow, which allows you to change gears, engage and disengage the torque converter lock-up and perform other functions.
Operating principle
A linear solenoid consists of the following main components:
* Coil: An electric coil that creates a magnetic field when electricity is applied.
* Plunger: The metal rod that moves inside the coil when electricity is applied to it.
* Spring: Returns the plunger to its original position when the power is turned off.
*Hydraulic Port: The port through which hydraulic fluid flows to and from the solenoid.
When electricity is applied to the coil, a magnetic field is created that attracts the plunger into the coil. This plunger movement opens or closes a hydraulic passage, regulating fluid flow and therefore the operation of the associated transmission component.
Types of linear solenoids
There are three main types of linear solenoids used in automatic transmissions:
* One-way solenoids: Control fluid flow in one direction.
* Two-way solenoids: Control fluid flow in two opposite directions.
* Three-way solenoids: Control fluid flow in three directions.
Control
The linear solenoids are controlled by the electronic control unit (ECU) of the transmission. The ECU determines when to activate or deactivate the solenoids based on input from the transmission and engine sensors.
Malfunctions
Faulty linear solenoids can lead to a variety of automatic transmission problems, including:
* Delays or jerks when shifting gears
* Gear slippage
* Inability to change gears
*Transmission emergency mode
Diagnosing and troubleshooting linear solenoids requires specialized tools and knowledge.