What Is a Kickdown Solenoid?by Geoffrey St. Marie
As opposed to a standard transmission, an automatic transmission changes gears for you. This applies to the manner in which the transmission down-shifts. A kickback solenoid aids in that down-shifting, offering a smoother transition.
The kickback solenoid is located within the transmission of your car. It helps the car to down-shift easier, while at the same time maintaining the desired level of torque as well as speed. In some models, such as the Porsche, this solenoid process may be activated once the vehicle drops below a certain speed.
The communication between the kickback switch and the kickback solenoid allows smoother transitions between down-shifts. The switch empowers the solenoid as long as the RPMs remain below a certain point specific to the vehicle. Thus the circuit between the two is usually open, causing shift speed to be as close to the "maximum speed" as possible. Once the RPMs exceed that limit, the circuit becomes open and the power to the kickback solenoid is no longer delivered.
In addition to its primary purpose, a kickback solenoid possesses other features that protect it from wear and tear. First, the solenoid is resistant to vibrations often created in the running of the vehicle. Kick back solenoids can also handle hotter temperatures and even "immersion in fluid."