Transmission Solenoid Warning Signs

What is a Transmission Solenoid?

A transmission solenoid or cylinoid is an electro-hydraulic valve that controls the flow of

transmission fluid flowing into an automatic transmission. These electro-hydraulic valves

control the transmission fluid inside the transmission chamber. In an automatic transmission,

shift solenoids provide a smooth gear shift of the car. Solenoids response to electrical signals

that is sent from the transmission control unit and with that information determines the ideal

time the transmission should be shifted resulting in the transmission control unit sending

signals to open the shift solenoids to allow transmission fluid to flow inside the transmission

chamber.

3 Main Types of Solenoids: The Lockup Solenoid, The Transmission Shift Solenoid and The

Transmission Control Solenoid. As the transmission control unit signals the solenoids, the

values will regulate the movement of the transmission fluid by opening and closing.

A solenoid is generally made from steel with a value and return spring. The solenoid coil has a

wire wound around it which generates a controlled magnetic field acting as an electromagnetic.

Designs may vary but the nine most common parts of a transmission solenoid is:

• The Valve Body
• A Spring
• An Inlet Port
• An Outlet Port
• A Plunger or Piston
• Lead Wires
• The Solenoid Coil Body
• The Coil Winding
• An Orifice

Your solenoid will stop working if any of these parts fail causing your transmission to stop

performing.

Causes of Transmission Solenoids Failure:

Transmission solenoid failure common causes include Electrical Issues such as applying

incorrect voltage to the coil. Dirty Transmission Fluid can cause the shift solenoid not to

function correctly and become stuck preventing it from opening or closing. Wear Down and

Failure can happen to any component over a period.

Signs of Solenoid Failure:

Check Engine Light: A failing EVP can set off the check engine light.

Delayed in Gear Shifting: A faulty shift solenoid can cause a delay in gear shifting.

Certain Gears Getting Stuck: The shift solenoid could have become damaged due to a gear

being engaged causing the transmission to be stuck in one gear.

Gears Slipping: If your vehicle tends to skip over a gear there’s a possibility that a specific

solenoid is damaged.

Vehicle Acts Sluggish: If your car is a bit sluggish than usual it could be a sign of a failing

solenoid that’s keeping your vehicle under third gear.

Won’t Upshift or Downshift: Solenoid failure can cause problems in shifting. Damage to the

solenoid body, wiring, or dirty fluid can cause transmission issues with the gears shifting.

Engine Continues to Rev while applying brakes: A faulty solenoid can cause your tachometer

needle to keep climbing as you apply the brakes.

Call Eagle Transmission Shop in Mesquite to help you get to the root of your problem. We are

leaders in providing solenoid repair and replacement.

We are here to get you back on the road again. We service Dallas and Surrounding areas like Forney, Seagoville, Rockwall, Rowlett and more.