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Too Much Transmission Fluid

Too Much Transmission Fluid

Even if you fill the transmission reservoir with the best rated transmission fluids, too much of it isn’t a good thing. Overfilling is fairly common but unless you remove some of the fluid, it can cause unnecessary wear upon the transmission.

If you felt signs that there is too much transmission fluid, you will want to check the dipstick of the transmission reservoir. They vary in their placement as some cars have them within the engine bay whereas others are located underneath the car.

Below is a list of the symptoms that too much transmission may cause.

Table of Contents

1. Dipstick Reading

If you ever have any suspicions that the transmission is overfilled, you should check the dipstick. Although you may have checked it after topping up the reservoir, it does expand when heated. Therefore you want to ensure that you read the dipstick correctly.

Whilst the engine is cold, ensure that the fluid is at the top end of the “cold” indentation of the dipstick. Once the engine is at its optimum temperature, it should be between be directly in the middle of the two markings.

2. Delayed Gear Changes

Whilst changing up and down the gears, you want it to smoothly change. However, if you have overfilled the transmission fluid, it will cause difficulty in shifting, which often results in delayed gear changes. This is due to the fluid turning foamy inside of the transmission, which is caused from excess fluid pressure.

If the pressure remains for a prolonged period, there will be extra wear and tear upon all the components within the transmission.

3. Leaks From The Transmission

As a result of the increased fluid pressure, many of seals may breakdown, which causes leaks to appear. As the transmission fluid will be a reddish color, it will be easy to distinguish it from other automotive oils that may form underneath a car. It’s important to note that the seals will need changing in order to effectively stop the leaking in the future.

4. Grinding or Whining Noises

Although a wide range of noises come from a faulty car, the transmission noise can be difficult to pinpoint. However, if you drive up an extended incline where the transmission is under load, you may be able to confirm that the noise is coming from it.

The cause of the noise is due to the foaming effect from the extra pressure that the transmission is under. Once the fluid is foamed up, its no longer able to properly pump around the transmission and lubricate key components.

5. Transmission Overheating

Another result of the fluid foaming up is that the transmission can begin to overheat due to the friction. The lack of lubrication is one of the worst things to happen and it can completely ruin the internal mechanism of the transmission. Due to the excess heat, it also increase the wear upon the seals, which will increase the leakage.

As a quick and easy solution to temporary cool down the transmission, you could attempt to use a transmission additive. They help to restore the original properties of the fluid, which can make the transmission operate as it should.

How To Remove Excess Fluid

The obvious answer to removing excess fluid from the transmission is to drain it out completely and refill the reservoir. However, not only is this time consuming but its an additional cost as you shouldn’t reuse the fluid.

The best way to deal with overfilled transmission fluid is to use an oil extractor, which vacuums the fluid out from the top of the reservoir.

procarreviews author

Written By Dan

About the Author

Dan is an automotive journalist and owner of over 10 cars ranging from supercars, tuned cars, classics and your good old beater cars. He always likes to get his hands dirty with nut and bolt restorations or detailing sessions using the best products on the market.

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