Problems to Face When There Is Too Much Transmission Fluid
Transmission fluid is the lifeblood of transmission. It ensures the smooth running of the engine and keeps the transmission temperature down since the gear generates a lot of heat due to numerous mechanical movements. Some people simply forget to change the fluid, which creates a bunch of problems. But, will there be any trouble if there is too much transmission fluid? Let’s find out.
Symptoms Of An Overfilled Transmission
Here are 4 common symptoms you can observe if your transmission is overfilled:
- Transmission overheating – caused by failure to negate friction
- Difficult and delayed shifting – due to foamy fluid
- Appearance of a fluid puddle below the transmission – inspect for leakage on the transmission’s seals
- Gear Slippage
What Happens to the Car When You Put Too Much Transmission Fluid?
The main function of transmission fluid is to minimize the frictions between the components in the gearbox. However, it can’t do its job properly when you overflow the fluid container. The response will be a cranky gearbox. Why does this happen?
Because of foam! Too much transmission fluid forms foam inside the gearbox. The formation of foaming happens when the rotating gears splash in the overfilled reservoir. It triggers excessive temperature and causes a chemical reaction, leading to the creation of foam.
The foam affects the viscosity of the oil. For this reason, the fluid does not flow properly through the gears when you shift them. The lack of lubrication will cause the transmission components to overheat, leading to mechanical damage and failure of the transmission.

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While the consequence is the same, automatic and manual transmissions response differently to too much transmission fluid. In an auto transmission, the gears will compress, causing the foam to implode inside. It will affect the hydraulic pressure and cause further damage because the auto gearbox relies on that pressure for working properly.
An overfilled manual transmission, on the other hand, will show issues with the clutch. The excess oil will leak from the vent that affects the clutch and results in a gear-shifting problem.
SEE MORE:
- Can You Drive When the Transmission Temperature Light Is On?
- Is It Possible to Skip a Gear in Manual Transmission?
How Much Fluid Should the Transmission Have?
You have to add half a quart at a time and keep taking readings with a dipstick. When it shows ‘full’, run the engine and put the gear in the ‘idle’ mode. Recheck the oil level when the engine is hot. Stop pouring oil when the dipstick indicates that the oil level is at the top end of the ‘hot’ mark. If the engine is cold, the level of the oil should be at the top end of the ‘cold’ mark. When the engine is neither hot nor cold, the fluid level should be in between these two marks.

Most transmissions have the capacity between 9 and 13 quarts. Check the owner’s manual for knowing about the exact amount. However, you should always add a little at a time to avoid too much transmission fluid.
You can’t overflow some gearboxes because of the way they have been designed. They have a system that will flow out or spill the extra oil.
Watch the video below to know how to check transmission fluid:
What Should You Do with an Overfilled Transmission?
If your car shows the symptoms of overflow, avoid complications and mechanical damage just by siphoning or draining the excess liquid. You can do this by using an extraction pump or a filler tube that you can buy online. Depending on the design of your car, it’ll either have a cooler line or a pan drain plug, both of which you simply remove to drain the liquid.
Final Words
As you see, an overfilled transmission is not a complicated problem to fix and to avoid. But many drivers still have trouble with it as they ignore it until it causes many serious damages.
Therefore, everything you should do is to always take care of your car and check it from top to bottom at least once a week. Bear in mind that not only the engine is important but also other parts as well, especially for the transmission.