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What Happens When There Is Too Much Transmission Fluid?

too much transmission fluid

It’s no secret that the transmission is arguably the second if not most important assembly in your vehicle. It competes with the engine as the most crucial car component that keeps your car efficiently running.

The transmission is packed with a lot of mechanical movement. This is especially the case for manual transmissions that have a gearbox. With that said, transmission fluid is needed to keep the temperature down. However, too much transmission fluid can pose a problem rather than a benefit. Stay tuned as we discuss this issue below!

You also can read more: Top 10 Most Common Transmission Problems You Have To Know

What Happens When There is Too Much Transmission Fluid?

One of the main symptoms of a transmission that has too much fluid is a cranky gearbox. The fluid that you put in your transmission is supposed to be used to lessen friction. However, too much of it will cause the opposite.

The reason for this is because of foam. Yes, your transmission will have foam present inside it as a result of too much fluid. A chemical reaction will occur between the excessive amounts of fluid and the heat present inside the assembly.

Once foam forms inside, its viscosity will be a hindrance towards the transmission every time you’re shifting gears. This is because unlike oil, it doesn’t flow properly through the gears. This problem can branch out even further.

For example, since there’s no lubrication, the transmission will heat more. The cooling agent inside will be neutralized and thus, causing mechanical damage due to overheating.

For automatic transmissions, the foam can implode as a result of the compression of the gears. Imploding inside can cause further damage since an automatic transmission’s reliance on hydraulic pressure does not work well with foam.

On the other hand, if you have a car running in a manual transmission, damage can occur through the clutch. Every time you use your clutch (which is as often as you use the brakes), will cause shifting problems. This problem comes from a leak.

The leak is a result of an overfilled transmission, which then goes through the vent which affects the clutch every time you use it. Both automatic and manual transmissions are equal when we’re talking about the consequences of overfilling your transmission with liquid.

It’s not the only symptom to look after. Other signs that the transmission has too much liquid is oil starvation and overall transmission damage. The domino effect of adding too much liquid can potentially cause extreme consequences, which is why it’s a must for you to know the proper way of putting transmission fluid.

What Should I Do If It’s Overfilled?

As scary as the consequences may sound, you can just avoid it by siphoning the liquid from the transmission. It’s relatively easy to do this since all components of a vehicle that uses liquid agents have drainages.

Drain the liquid either by using a filler tube or an extraction pump that you can buy online. Depending on your car’s design, it’ll either have a pan drain plug or cooler line, both of which you simply remove to drain the liquid.

Here’s a helpful tutorial on how to drain excess transmission fluid:

How to Correctly Add Transmission Liquid

Adding too much transmission fluid is entirely the car owner’s fault (if he was the one who put it). In our experience, many new car owners tend to belittle the importance of getting the transmission fluid portions correctly.

Some think that as long as you pour a generous amount, your communication will be good to go. This is where the first problem starts because adding transmission fluid is not something that you can carelessly do. It’s not like adding oil to a frying pan.

There are a particular measure and practice used in adding transmission fluid. For starters, you should put around 450-500 ml of liquid at a time. Once you’ve added this amount, use the dipstick, which is designed as a liquid indicator, to your advantage.

From time to time, the dipstick might show that it’s full of liquid even after putting the first 500 milliliters. However, this is not the case all the time. Hence, start your engine after the first batch and leave it to run in idle for around 3-5 minutes.

Afterward, go back to your dipstick and check again. At this point, it should indicate that the transmission fluid is not full anymore. Keep adding batches of transmission liquid until the dipstick reads that it’s full.

Wrapping it Up

At the end of the day, an overfilled transmission is a simple problem to solve and to avoid. Many people still have a hard time with it, and that’s because they overlook it until the problem has caused too much damage.

Always be a responsible car owner and check your vehicle from top to bottom at least once a week. Remember, it’s not only the engine that matters but the rest of the parts as well. And that’s true, especially for the transmission.

If you liked this article, feel free to comment and share! Happy driving!

Steven K. Galloway