What Should You Do After Adding Too Much Transmission Fluid?

Many people understand that transmission fluid is really essential in keeping smooth operation of the engine in their car. Because of friction, the transmission often generates a lot of heat, so you need to use transmission fluid for the engine to keep it from damaging your car.

Many drivers rarely change the transmission fluid, and even those who usually have it done by a professional service garage. In fact, you could replace this fluid on your own just by using a couple tools available. But how do you know the suitable level of transmission fluid for normal functioning of your vehicle?

What is The Suitable Transmission Fluid Level?​

In general, you should only add about half-a-quart fluid each time. Even when the dip-stick is really not full, it would show that. Start the car and let it running for approximately 5 minutes, then check the level again when the engine is already warm. Add in as much transmission fluid as needed till the dip-stick shows full.


The level of transmission fluid in a hot engine needs to be on the upper part of the hot mark, while in the cool one it must be on the upper part of the cool mark. Make sure that the fluid level is also in the safety zone between the 2 marks at a warm engine.

Most types of transmission fluid often require from 9 to 13 quarts to be full completely. Depending on whether you are replacing, draining or topping, the amount of transmission fluid that you add will be different. Again, remember to add in little amount at the same time to prevent putting too much.


What Would Happen When You Put Too Much Transmission Fluid?​

If you overfill the transmission fluid to the car’s engine, it would foam and result in unpredictable gear shifting. Moreover, oil starvation as well as transmission damage are other possible issues.

In an engine or a transmission, foaming happens when rotating elements (rotating parts in crank-shaft weight, tranny in the engine) splash into the overfilled oil/fluid reservoir or crankcase. This will result in excessive fluid temps, which make the transmission fail and the tranny fluid degrade very quickly.

When you overfill an automatic transmission, the fluid would foam, resulting in problems with transmission damage, gear shifting or oil starvation. While an overloaded manual transmission would lead to fluid-leak in the vent and gear shifting becomes an issue once the clutch is pressed. All transmissions, auto or manual, have some ways to relieve excess pressure.

Adding too much amount fluid could also cause damage of elements and early failure due to excess pressure, which is in shift from minimum to maximum (often 300 PSI) and makes some elements of your car totally unstable.

When you attempt to change or reverse the gears more, the problem could get even worse. You can notice easily how that would do a lot of damage to the transmission. The pressure could result in friction and break parts, push out snap ring easily, leading to serious damage or sudden failure.​

Many car models these days are made with transmissions that have a pressure valve to control pressure after a pump. Nevertheless, as mentioned earlier, excessive pressure could lead to the wearing out of several elements, including the valve, thus make it fail.

As a result, this failure will in turn generate pressure related issues in other components of engine. In other words, putting too much fluid can result in to pre-mature damage of the vehicle’s engine over time. In addition, it might most likely prevent any warranty that you may have if the reason for this failure is attributed to overfilled transmission fluid.

In fact, there are still some car models that are made with transmissions which could not be overfilled thanks to modern design, which has a hole at its side to allow any excessive fluid to come out.

How to Deal With Transmission Fluid Overfilling?​

When you put too much transmission into the engine, you can have it resolve by a service garage or drain it on your own by applying a filler tuber changing the cooler line or taking the pan drain plug out. It would take time to suck out the transmission fluid but you just need to hold the filler tube till it nearly reaches your mouth’s cap, then pull out the tube by your thumb, stick the end to a can and drain it.

You can also make use of some reasonable extraction pumps, which are available in most car parts shops. After draining, you will have to change the fluid to the suitable level if it is not in appropriate condition.


Wipe a dip-stick on the white cloth or wipe, and check the color left, which has to be clear. If you notice some black spots or it is a little brown, you should get the transmission fluid replaced immediately. Due to dirt, temp degradation, metal or friction particles, the thickening of transmission fluid can block the drain and lead to foaming.​

If you are interested in driving your vehicle in stressful condition where transmission is hotter than usual, you should frequently check the transmission fluid for burning and wearing out.

Some people will say changing the transmission fluid is not really necessary, but it is actually not correct in most cases. The heat generated when running could get so hot that it begins to lose the lubricating abilities and the seal would start to harden, which result in pressure leaks and losses. As a result, the transmission will be damaged in those conditions.

To sum up, you should keep a close eye on the amount of transmission fluid that you add to save a huge amount of repairing cost in the long run.​



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4 thoughts on “What Should You Do After Adding Too Much Transmission Fluid?”

  1. Someone put to much transmission fluid in my car now it want go in drive have to put it in first gear to make it go could it be my transmission flooded

  2. Changed out transmission and put to much fluid in it and drove until got hot. I drained all fluid and readded correct amount however still doing some and not ahifting. I know probably did some damage but is this damage fixable or should I just go and by yet another transmission?

  3. Its good to know that putting too much transmission fluid could result in early failure to your transmission. My wife’s transmission recently ran out of fluid and she accidentally put too much fluid in when she was repairing it. I’ll let her know that she should go to a repair shop before her transmission breaks early on.

  4. I didn’t know that putting too much transmission fluid in my car could cause problems! What about the foam would cause problems in your transmission? I’m going to go make sure the level of my transmission fluid is right.


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