Can low transmission fluid causes overdrive light to flash? It can

There’s no doubt about the fact that overdrive is an important component of modern vehicles’ transmission systems. And one of the FAQs about these transmission systems is; can low transmission fluid cause overdrive light to flash? Yes, it does, let’s see how

How Transmission Fluid Can Trigger Overdrive Light To Flash

There’s a way in which the transmission fluid of a vehicle, if low, can trigger the overdrive light to flash. As said earlier, the overdrive is a core component of the transmission system.

Its job is to enable the engine to operate at lower power but make the car move faster. As a result, the vehicle is able to achieve better fuel efficiency and often quieter operation.

To explain how the overdrive system works and how transmission fluid can trigger the overdrive light to flash, let’s first get to know about another key component of a vehicle’s transmission system—the transmission solenoid.

Now, the transmission solenoid or “solenoid pack” generally comes in a pack that is installed in the transmission control module, transmission control unit, or transmission valve body.

This electromechanical valve basically controls the flow of transmission fluid within a vehicle’s entire transmission system. It works by detecting the transmission fluid pressure and then opening or closing as needed to regulate the flow of the fluid within the entire transmission system.

Besides that, it also activates overdrive, which allows the vehicle to move faster without straining the engine.

Now, if the transmission fluid level drops too low, the fluid pressure, which the solenoid relies on, becomes hindered. Consequently, the solenoid becomes erratic and disrupted such that it cannot activate the overdrive.

The overdrive light, which is commonly known as the “O/D Off light” is designed to flash if the overdrive function becomes inactive. This can happen maybe because the overdrive is switched off by the driver or there’s a problem with it.

What Are the Symptoms of Low Transmission Fluid?

Apart from a flashing O/D Off light, other symptoms of low transmission fluid include, but are not limited to the following;

  • You hear strange noises coming from your transmission system while you’re driving.
  • You notice a burning smell coming from your car.
  • You notice a red fluid leaking underneath your vehicle.
  • Your vehicle is slipping gears.
  • Your car is picking up gears too slowly.
  • Your vehicle is accelerating poorly.
  • The transmission or check engine warning light comes on.

What Happens If the Overdrive Light Flashes?

If your overdrive light is flashing, it means something is wrong with your overall transmission system. For example, it could be that your overdrive is problematic due to a low transmission fluid level or so.

In that case, the first thing you should do is check your transmission fluid level and top it back up if necessary.

Is There Another Cause that Triggers a Flashing Overdrive Light?

Awhole range of issues can trigger the light to flash. These include but are not limited to problems with your;

How Much Does It Cost To Fix This Issue?

The answer depends on the cause of the issue. As said above, there are many causes including but not limited to a problematic solenoid, transmission fluid, speed sensor, wiring harness, valve body, and catalytic converter.

  1. Solenoid—-The average cost to diagnose and fix a solenoid ranges between $150 and $400.
  2. Transmission fluid—The total cost to diagnose and fix transmission fluid issues is anywhere between $300 and $500.
  3. Speed sensor—The average cost to diagnose and fix speed sensor issues is about $282–$326.
  4. Wiring harness—The average cost to diagnose and fix wiring harness issues can go up to, and sometimes, above $1700, depending on the severity of the issue.
  5. Valve body—The average cost to diagnose and fix valve body issues is between $300 and $1000.
  6. Catalytic converter—The average cost to diagnose and fix catalytic converter issues is between $945 and $2475.


Nowadays, most cars and trucks(both petrol and diesel, automatic or manual) come with an overdrive function to provide the highest gear output with minimum engine input.

This ensures a faster, smoother, quieter, and more fuel-efficient drive. If there’s a problem that causes this functionality to disengage, that will trigger the O/D Off light to flash. A common culprit is low transmission fluid.

Scroll to Top