low transmission fluid symptoms

Will a Slightly Overfilled Transmission gets damaged?

In Transmission by Magnus Sellén2 Comments

transmission fluid

Car owners will listen keenly for any screeching noises and stay alert for changes in shifting because they might point to problems in transmission, which may arise from deteriorated transmission fluid.

You need to keep track of your car’s transmission fluid to change it at the right time and avoid these problems.

While there is a consensus that transmission fluid needs changing, different vehicle manufacturers often give out schedules based on the model of the specific vehicle.

The recommended distance for changing your transmission fluid for most manufacturers is around 100,000 miles, but this may be too long. A lot of mechanics would suggest a change every 50,000 miles for optimum maintenance.

While it is an easy task which you can do by yourself, you should be wary of overfilling transmission fluid, which could affect your gear change.

The basic working of a transmission

low transmission fluid symptomsIf we talk about the manual transmission, it’s simple to understand how it works. A manual transmission resembles an automatic one but with a few differences. The significant difference is that manual transmissions are operated with a stick for shifting the gears.

There are multiple gears of different sizes inside the transmission where the stick connects. Here, since everything is operated manually, all you need is lubrication to keep the gears inside the transmission cool and run smoothly.

Transmission oil is used to achieve that – It is a little different than engine oil but more or less serves the same purpose.

However, the case of an automatic transmission is a little different. These transmissions also contain gears but an additional component known as the torque converter, which makes use of the transmission fluid we are talking about here.

Only, here the transmission relies entirely on the Trans fluid to operate and without it, the transmission would not at all function. The liquid for automatic transmissions is different from manual transmissions. Here, putting too much transmission fluid, above the full mark even, can cause rather adverse effects.

Will it cause damages to my transmission if it’s overfilled?

transmsision fluidSimilar to the engine itself, transmissions also generate a lot of heat which needs to be cooled down. In manual vehicles, that is achieved by using transmission oil as we talked about.

In automatic cars, the transmission fluid serves two purposes, one, as a cooling and lubricating agent and two, as the fuel for the transmission to work.

While this fluid is critical for the smooth operation, too much fluid in the transmission can ruin the transmission itself. That is because, too much fluid in the transmission will submerge the gears entirely in the fluid, which would make the fluid foam up.

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Because of the foaming and very little room for air, the excessive transmission fluid would overheat the transmission instead of keeping it cool, and without room for air, depressing the clutch would result in fluid trying to ooze out of the transmission, compromising the sealing in the process.

This becomes dangerous in automatic vehicles even more.

Consequences of overfilling transmission fluid

As we discussed some major causes could occur if you are overfilling your transmission fluid. Here are some of the most common:

  • Overheated Transmission: Your transmission may overheat if you are overfilling your transmission fluid because of the increased pressure and friction.
  • Transmission fluid leakage: When you add too much fluid, it will cause high pressure inside the transmission, which may cause your transmission to leak fluid.
  • Erratic Shifting: Because of problems with the pressure and the shiftings, you may find issues with your car like erratic shifting if you’ve overfilled it.
  • Foamed fluid: When you have overfilled your transmission fluid you may experience things like foamed transmission fluid inside of the transmission. Check further down for more explanation.
  • Oil starvation: If your transmission fluid is foaming, it may get stuck to the upper part of the transmission and on the gears and everywhere it shouldn’t be inside of the transmission. This can cause the transmission to seize if you are unlucky.
  • Reduced Fluid Lubrication: As we discussed before, the transmission fluid may foam up and this will cause the lubrication to get a lot reduced. This can cause heavy wear on your transmission in the long run.

Since automatic transmission relies on the fluid to work, too much liquid in the transmission will cause erratic gear shifting. That could result in either early shifts or delayed ones along with jerks. The transmission may also make odd noises in the process.

Excessive fluid in the transmission may also starve it from the oil itself. The most critical thing about adding too much transmission fluid is that it will cause a big difference in the pressure inside the transmission itself.

A certain amount of pressure inside the tranny is maintained along with the fluid which is which there is a limit given on the dip stick. Too much of the fluid will cause an increase in the pressure inside the transmission and you can think of the damage that can cause to it.

Will a slightly Overfilled Transmission gets damaged?

transmission dipstickA slightly overfilled transmission won’t take any damage if we are talking about amounts like 0.3 litres/0.3 quarts. If you are overfilling your transmission with a liter or more above the max sign,  your transmission could get damaged.

Transmission fluid serves some functions in your vehicle. It is mainly used for lubrication, but conditions your gaskets, controls your transmission temperature and protects the metal surfaces and movable parts from wear, which may arise from friction.

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Overfilling transmission can affect the operation of your car. You may experience leakage on the transmission seals, which could cause a puddle to develop under the transmission.

You could experience difficulties when shifting and may undergo overheating. These symptoms will be caused by overfilling transmission fluid and may attract more significant damage to your car.

If not corrected, too much transmission fluid could cause seal damage, as well as affect the consistency of shifting. Seals, which prevent leaking when rotating shafts combine with solid components, are very susceptible to excessive fluid and could be at a higher risk of damage.

There will also be an increase in temperature in your transmission since the foamy excess fluid will not adequately address the component friction.

How to know when your transmission fluid needs changing

Transmission fluid will wear out over time, primarily when engaged in heavy-duty use. You will need to change your transmission fluid quicker if you pull trailers or heavy loads, or make frequent stops such as by driving in the city.

More massive duty driving causes the transmission’s operating temperature to increase, which may wear out the oil faster. If the usually red or green transmission fluid is darker and smelling burnt, it will need to be changed.

If you are experiencing slower or hindered gear shifts, it may be a result of deteriorated transmission fluid. It serves both as a lubricant oil and hydraulic lift, which helps to facilitate gear changes. Transmission fluid also cools down the transmission.

Reduced efficiency of these functions could be a sign of transmission fluid that needs changing. You should also consider changing the transmission fluid if it has debris and any foreign particles.

What do you need to consider before changing your transmission fluid?

The typical signs that suggest your transmission fluid needs changing do not necessarily mean that you need to do it right away. Unless you are experiencing transmission failure, you can schedule a fluid change.

You will need to consider the manufacturer’s suggestion concerning the mileage covered before making your decision, as well as take some time to find a budget-friendly service provider.

Understanding the specifications by your car’s manufacturer could also help you choose the right option between flush and drain fluid changes during maintenance. It will also provide information on the compatible transmission fluid options, as well as any steps involved in the cleaning and maintenance of other parts such as the filter.

So how much fluid should you add?

Transmission fluid shares some similarities with the engine oil. How you would get a different reading from the engine oil dip stick when the engine is cold, and when it is hot, you will get the same results when checking the transmission fluid level.

But there are two situations where the tranny fluid can be checked. It can be checked when the engine is hot as well as when it is cold. Here are a few points to check your transmission fluid:

  1. Park your car on a level surface.
  2. Pull out the dip stick
  3. Wipe the stick with a lint-free clean cloth and reinsert it
  4. Pull it out and check the fluid level
  5. If the engine is cold, check the cold mark
  6. If the engine is warm or still running, check the hot mark
  7. If the fluid level too much below marks according to the situations, fill it to complete
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Usually, transmission fluids don’t need to be changed that often. Certainly not as much as engine oil. In the case of automatic transmission fluid, the color of the fluid should be fairly red or pink and the smell shouldn’t be like it’s burnt. Similarly, in manual transmissions, the fluid should not be dark in color but pink reddish.


Did you know that replacing your transmission fluid can be less expensive than motor oil changes cumulatively? Finding the right oil and keeping up regular checks will help you ensure great preventive maintenance. If your transmission fluid is old, discolored or carrying a burnt aroma, you may need to change it.

The lack of lubrication can cause damage to seals and other components, which could affect the lifespan and functioning of your car. It could also cause harder shifting.

Following the manual and manufacturer’s direction for replacing the transmission fluid could help protect your car from total transmission failure. To avoid this expensive problem, you should follow the procedural and fluid specifications made.

If you are manually changing your transmission fluid, remember to take safety precautions. You should also monitor the amount since overfilling transmission fluid can affect your whole driving experience.

So if you have overfilled your transmission, it’s an excellent idea to tap out some through the plug or through the dipstick to get the level right. Overfilled transmissions can cause severe damages to your transmission in the long run.

If you have any other questions about transmissions you can search for information on our site or leave your comment down below, I will answer your questions as soon as possible.

Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

    1. Sir,

      I’ve changed my CVT. Total drained is found 3550ml ~ 3600ml while 4Litre pack is inserted in Daihatsu MIRA ES (660cc).
      Minor waste could be considered touching the hands or elsewhere.
      Now, guide me as working so far is ok with none observation about burnt smell or delayed shifting. So tell me if that extra is of any harm.
      Dipstick is weird, in cold the level appears to be unknown as its all over while on running engine which us just idle after a drive of 1~2 km is not even touching the third higher spot on dipstick.
      It was my first CVT oil change on 66000 kms i.e. 41000 miles.

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