Symptoms Of Too Much Transmission Fluid: What Should You Do?

Many different fluids run through your car to make things work. They work tirelessly behind the scene to ensure a seamless driving experience. From the radiator oil, and motor oil, to air conditioning refrigerant, fluids are the lifeline behind your automobile.

Among such many fluids is the transmission fluid. The appropriate transmission fluid levels can protect you from costly repairs. But does too much transmission fluid equate to higher or superior performance? Though many understand the importance of changing their engine oil, not many understand the roles of transmission fluid, when to change it, and at what appropriate levels.

First off, before we jump into the consequences of an overfill and get dirty, let’s tackle a few problematic areas, shall we?

How Often Should You Change Your Transmission Fluid?

As earlier mentioned, most people are aware of when and at what intervals to change their motor oil but are clueless when it comes to transmission fluid. As with motor oil, transmission fluid breaks down and gets contaminated with debris and particles over time.

Though the transmission fluid doesn’t require frequent change compared to your motor oil, it’s prudent that you keep an eye, checking on it regularly.

When your transmission fluid is low, you’ll notice a decrease in power or performance when shifting gears. During such cases, the risk of damaging internal gears is high since parts grind together due to low or lack of lubrication.

Hand pouring transmission fluid on the car’s engine.

Two variables determine the frequency of transmission fluid change namely;

  • Your mode or style of driving
  • Your car’s transmission type
  • Your car’s make or model

On average, different car manufacturers advocate for a change in transmission fluid every 30-60,000 miles. However, it will vary based on the variables above and it’s always best to consult or follow your manufacturer’s recommendation.

Harsh weather conditions, stop-and-go driving, and towing heavy loads can strain your transmission and transmission fluid. You’ll want to keep an eye on your fluid levels if operating under such conditions.

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How To Know If Your Transmission Fluid Is Low

The main indicator of low transmission fluid is transmission overheating. This means that the fluid levels are low or depleted. Though the levels in transmission fluid won’t necessarily bring the car to a stop, it will make the engine rev higher with no corresponding output in power.

Look out for signs of ground leakage where you park. If your vehicle comes with a dipstick, check your levels regularly during an oil change.

So, how can you tell that your transmission fluid is low? Below are just a few of the tell-tale signs;

  • Formation of puddles under your car pointing to a fluid leak.
  • Roaring sound during acceleration or negotiating a corner may point to an issue with your transmission.
  • Chattering during take-off. It typically feels as if you are driving over rumble strips. It’s a common sign of low transmission fluid.
  • Warning lights. Modern-day cars come equipped with the latest technologies to not only indicate issues with your engine, but also transmission.
  • Difficulties when shifting gears.
  • A slight burning smell coupled with an unusual tart smell can be a pointer to issues with your transmission fluid.
Man’s hand on his gearstick while driving.

At this point, you may be wondering what would happen if your car totally runs out of transmission fluid.

It’s very simple. Your car will most likely not shift or go into gear. This normally applies to automatic transmission vehicles. Unfortunately, allowing your vehicle to arrive at such a point will lead to extensive or costly repairs.

That’s why keeping an eye on the above indicators is such an essential thing. You could further use the services of a professional to check out your car when in doubt.

So far, we’ve only looked into issues with low transmission fluid. To most motorists or vehicle owners, it can’t get any much worse with too much transmission fluid or an overfill, can it? Well, that’s where you are wrong! According to car bibles, there are three fundamental effects of increased automotive transmission fluid;

1.     Increased Transmission Fluid Pressure

Too much transmission fluid beyond the required amount leads to increased pressure within your automotive components. The resultant effect of increased transmission pressure is air contamination.

The rotating gears splash transmission fluid within the chamber causing a chemical reaction leading to the formation of foam or bubbles. The build-up of foam or air bubbles in the transmission fluid hampers the fluid’s lubricating ability and its overall viscosity.

Instead of delivering thin layers of oil in between the metal parts, pockets of air are delivered hampering lubrication. This enhances wear and tear since metal parts grind against one another

Apart from premature wear and tear, shifting becomes more difficult and sluggish, and the car will most likely feel unresponsive or slow.

2.     Overheated Transmission

When we talk about a gearbox with inadequate lubrication, we do not necessarily mean low levels. It can also refer to too many transmission fluid levels. Evaluating both sides of the coin, though overheating may not immediately affect the transmission gears, it may lead to breakage of the seals which safeguard the fluid within the gearbox.

Once the seals break, they can no longer contain the fluid within the gearbox, leading to lower levels of fluids resulting in overheating.

On the other hand, too much transmission fluid can lead to fluid leakage from the gearbox, robbing the transmission of the vital fluid. The resulting effect may be the loss of shifting ability.

3.     Transmission Failure

A combination of leaking or broken seals increased fluid pressure and grinding metal parts could lead to faster disintegration or breakdown of the whole transmission system. Increased fluid pressure sometimes exerts its toll on both the transmission lines and the gearbox.

A car owner needs to be aware of the dangers of too much transmission fluid since it’s rife that the transmission may fail.

Excessive Transmission Wear

A transmission’s moving parts require the recommended or right amount of lubrication to function properly. Lubrication will never be the same as a result of too much transmission fluid. What most people don’t realize is that the amount of transmission fluid is directly proportional to the pressure inside your transmission.

As such, an overfill subjects your transmission moving parts to high pressure leading to excessive wear and tear. Such an occurrence could lead to complete transmission failure.

You may end up going for a rebuild that may set you back a few hundred dollars. However, for a complete transmission failure, there’s no option other than getting a complete transmission replacement.

Mechanic working on car transmission.

Slightly Overfilled Transmission?

Are you worried that your transmission is overfilled? Don’t fret. If you didn’t put too much in, you should be okay. Overfilling it by around .04 quarts should be okay. Your transmission is still safe. However, filling it with 1 quart or more will definitely hamper or worse, damage your transmission. You should consider draining it. Try as much as possible to hit the recommended line when refilling the fluid.

Now that you have the potential consequences of transmission overfill in mind, it is crystal clear that this is a serious problem that should be resolved ASAP. As such, below are some common pointers or symptoms of an overfill;

1.     High-Level Dipstick

The first instinct that comes to a driver’s mind with suspicion of an overfilled transmission fluid is to run and check their dipstick to ascertain the exact fluid levels. Though it may be as simple as it seems, it’s not always a reliable method.

It’s always advised to check the dipstick when the engine is running. Always turn on the ignition and let the engine purr for five or more minutes. This is aimed at giving the transmission fluid an even consistency. Your fluid will turn thick during low temperatures and may stick to the inner lining of the dipstick shaft.

Therefore, running the engine before checking the dipstick ensures uniform viscosity, allows you to make accurate dipstick level readings, and ascertain the quality of your fluid ( lower viscosity allows debris or contaminants to loosen up).

If you are using the dipstick method to diagnose an overfill, we suggest you heat things up a bit by running your vehicle to ensure accurate readings.

2.     Difficulties in Shifting & Changing Gears

Such difficulties always point to problems with the transmission system and in some cases, overfilling your system may be the underlying problem.

Too much transmission fluid leads to a build-up of pressure which creates foam hampering the fluid’s lubricating ability. A chain of other problems may result such as seal breakage and fluid leak that in turn makes gear shifting hard.

3.     Fluid Leakage

Fluid leakage may be a result of seal breakage due to wear and tear. However, having an excess of transmission fluid may also lead to unwanted leakages. Such leakages are manifested by puddles under the car just below its transmission. It’s easy to distinguish it from other fluids since it’s reddish in color.

As earlier noted, seal wear and tear due to inadequate lubrication that comes with an overfill is likely to blame. The resulting pressure too from the overfill will force the fluid to exit leading to spillage.

4.     Whining, Grinding, or Humming Transmission Noise

It’s typical for transmission systems to make noises or sounds when in operation since it’s composed of several moving parts. However, such sounds are not easily noticeable since the transmission system borders the engine. However, if you drive your car regularly, then such noises are hard to bypass.

Such noises are a clear indication of inadequate or excess transmission fluid in the system. Grinding comes from the cogs rubbing against one another caused by low or lack of lubrication as a result of an overfill.

5.     An Overheating Engine

While an overheating engine may be caused by multiple factors, the most common causes are attributed to low or poor lubrication. Understand that the engine oil is responsible for cooling the engine. However, any issues with your transmission may result also in an overheated engine.

An overfill in your transmission prevents your transmission system from working optimally. And since the transmission is connected to your engine, the engine works harder to get your car moving. The extra effort easily heats up the engine leading to overheating.

How to Fix an Overfill

If you think you have an overfill in your transmission, quick or prompt action will aid you from pending, expensive damages. You could start by immediately doing the following;

Car transmission oil check using a dipstick.

1.     Park Your Vehicle on a Level Surface

Parking on a level surface ensures you get the correct level of your transmission fluid. Once parked. Turn off the ignition and allow the engine to rest for 20-30 minutes before popping off the hood.

If the car is dormant, turn on the ignition and allow the engine to heat up. We need the engine to operate as close to normal before reading the dipstick. Then, and only then, can you pop the hood.

2.     Checking the Fluid Level

Pull the dipstick from the transmission port and wipe with a clean, lint-free cloth. Slowly insert the dipstick into the port and remove it again. Check the fluid markings. This should give you a pretty good idea of the transmission fluid levels your car is operating on.

Check with your service or repair manual if you are not completely sure of how to do it. You could further take your vehicle to a trusted or certified mechanic.

3.     Drain or Syphon Excess Fluid

In case you have too much transmission fluid you’ll need to drain some. For some motorists, this isn’t that simple. Siphoning out the excess can be daunting if you don’t know what you are doing. A simple alternative is to locate the drain port in the transmission to let out the excess. Ensure you capture the excess fluid and dispose of it accordingly.

4.     Re-check Fluid Levels

Re-checking the levels ensures that the above process has achieved the desired results. By repeating the second stage, you’ll ensure that your vehicle operates with the recommended fluid levels.

Expert Tip: Alternatively, you could avoid the above process by exercising caution when filing up your transmission to the right amount.

As We Wrap It Up…

The right amount of transmission fluid ensures your car’s transmission operates at the desired levels. Having more or less brings about problems that may lead to catastrophic and expensive damages to your transmission system.

Since you may unknowingly end up with too much transmission fluid, it’s also vital that you know the signs and symptoms to watch out for, therefore taking the correct or timely appropriate measures.

We hope that this article sheds light and empowers you to take good care of your transmission, and as always we are always open to questions and comments.

Happy driving folks, and as always, get your shift together!

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!

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