Automatic transmission shift solenoid valve
The automatic transmission shift solenoid valve is an electromechanical device that controls the flow of transmission fluid in an automatic transmission (AT). It converts the electrical signal received from the automatic transmission control unit into mechanical action, directing transmission fluid to the required channels to engage or shift gears.
Solenoid Components:
* Electromagnet: Consists of a coil and a metal core. When current is applied to the coil, the core retracts, activating the switching mechanism.
* Switching mechanism: Consists of a plunger and a valve. The plunger is controlled by a core, and the valve opens or closes passages for transmission fluid.
* Housing: Encloses the electromagnet and switching mechanism, providing a seal and protection against fluid leakage.
Working principle:
1. The automatic transmission control unit sends an electrical signal to the solenoid solenoid.
2. The electromagnet coil becomes electrified, creating a magnetic field.
3. The magnetic field pulls in the metal core.
4. The core pushes the plunger, which, in turn, opens or closes the valve, directing the flow of transmission fluid through the required channels.
5. This causes a change in transmission fluid pressure, which causes the friction packs and brake bands to engage or disengage to change gears.
Types of Shift Solenoids:
There are many types of shift solenoids, depending on the design and function of the automatic transmission:
* Gear shift solenoids
* Shift Solenoids
* Torque converter lock-up solenoids
* Pressure regulation solenoids
Malfunctions:
Faulty shift solenoids can lead to shifting problems, transmission fluid leaks, or automatic transmission failure. Common faults include:
* Broken or short circuited electrical wiring
* Sticky or clogged shift mechanism
* Transmission fluid contamination or leakage
Repair:
Repairing shift solenoids usually involves replacing the faulty solenoid. This requires removal and disassembly of the automatic transmission. In some cases, the solenoid can be repaired by cleaning or replacing individual components.