Should I Check Transmission Fluid Hot or Cold and How to Check?

Just like an engine relies on engine oil, automatic transmissions are lubricated with transmission fluids. The transmission system has several moving components rubbing together, just like in the engine. These components will only work smoothly when you lubricate them well. Having a fluid leak may have a great negative impact on both the transmission components and the vehicle. It is, therefore, crucial to have the right amount of transmission fluid. So, do you check whether the transmission fluid is hot or cold?

This is a major question that most car owners would like to know about. Checking the transmission fluids regularly is the only way to ensure that you have the right fluid in the system. Some car manuals give you the mileage on when to check the transmission oils. However, for some reason, you might need to check it earlier than what the manual states. Here is more information on how to check if transmission fluids are hot or cold.

Check Transmission Fluid, Hot or Cold

Should I Check Transmission Fluid Hot or Cold

Lubricating the transmission parts saves them from friction, corrosion, and wear and tear. For them to keep their performance and maintain their functioning, then lubricating them with transmission fluid is the only secret. It is crucial to check the transmission fluid since the functioning and health of the transmission depend on it.

Checking this fluid should be a regular task. Regular check-up makes you aware of the arising problems in the vehicle. You should also check it when you notice some downgraded performance and unusual activity in your vehicle. Some signs that there is something wrong with your transmission fluids are episodes of engine stalling and screeching noises. Low transmission fluid in the system may also result in overheating of the transmission, gears getting stuck, irregular car shifts, and a slipping transmission.

The decision on whether to check transmission fluid hot or cold depends on the type of vehicle you are using. Most mechanics recommend checking the transmission fluid when both hot and cold. This helps you to cross-check the levels of the fluid when both hot and cold. The reason why you should check when hot or cold is that the fluid expands when heated.

When you have been running your vehicle for a long time and then check the fluid level when hot, it may appear to be high, while in the real sense, it is low. If you have to check it when hot, then you do not do that after driving for a long period. This is because the fluid continues to expand the hotter it gets.

Therefore, you check it when it is normal hot as if you have been traveling for around 10 miles or a little longer during the winter season. If the fluid has been working for more than 100,000 miles, you need to change both the filter and fluid. (Some vehicle transmission systems have no filters). This increases the durability of your transmission system. Make sure that you use the right modern synthetic transmission fluid for your vehicle.

Read Also: What is Transmission Fluid Color?

How to Check Transmission Fluid

The method of checking transmission fluids depends on if the vehicle is using manual or automatic transmission and also if you are checking it when hot or cold. Below is the process to follow: You can also go through this video to follow the process.

Checking Transmission Fluid When Cold

Step 1: Prepare the Vehicle

The first thing to do is to park your vehicle on a firm and flat surface. Put the vehicle on parking mode and start the engine. Run the vehicle to start the process. Transmission fluid should be checked when the vehicle is running. Can you check the transmission fluid without the car running? Some vehicles recommend you check the fluid when the engine is off; thus, it is crucial to consult your owner’s manual.

Step 2: Find the Dipstick

Open the vehicle hood and look for the transmission dipstick. The dipstick should have a handle with either an orange or red ring. The dipstick in front-wheel drive vehicles sticks from the transaxle. For rear-wheel-drive vehicles, look for the dipstick behind the back of the engine.

Step 3: Remove the Dipstick

Once you locate the dipstick, remove it and wipe it with clean clothing. The transmission fluid dipstick has two markings on it. There are hot and cold ranges. In the ranges, you find to add full markings on the dipstick.

Step 4: Insert the Dipstick

When the dipstick is clean and dry, insert it into the transmission fluid. Remove and take the reading. Some people may think that transmission fluid dipstick is hard to read, but that’s not the case. The right level of the fluid should be between the Add and Full readings. Some dipsticks may have Low and High markings while others have Min and Max. If it goes beyond full, then the fluid is excess, and if it goes below add, then you need to put more transmission fluid.

Step 5: Re-insert the Dipstick

After the first reading, do not settle on it without confirming. After checking the level, the first time, wipe the transmission fluid dipstick with a clean cloth and repeat the process. Dip it in the transmission fluid and get the reading. If the transmission fluid level is low, there is a high probability that there is a leak. In this case, you require to identify the leak and have t fixed soonest possible.

Step 6: Check the Transmission Fluid Color

Transmission fluids are bright red. If the color in your fluid has a darker or lighter shade of red, then it is okay. It should also not have any sort of deposits, bubbles, and odor. If it is dark brown or has a burnt odor, then it is overheated and needs to be changed.

Step 7: Check Transmission Fluid Consistency

Before you finalize the transmission fluid check, look at its consistency. Put a little transmission fluid on a paper towel and see if it spreads. If it fails to spread, the fluid is too thick and needs to be replaced.

Step 8: Put Back the Dipstick

If the level, color, odor, and consistency of the transmission fluid are good, then put back the dipstick completely and close the car hood. In case the level is low, then add more transmission fluid before putting back the dipstick. If the color is brown or has odors, it means that it is contaminated and needs to be changed with immediate effect. If you notice any leak, you can learn how to fix a transmission fluid leak or contact a mechanic.

Read: Can I use 10w30 Instead of 5w30? All That You Need to Know!

Checking Transmission Fluid When Hot

The process of checking transmission fluid when hot is almost the same as when checking it when cold. However, there are some crucial things you need to understand. For you to get an accurate reading when the engine is hot, consider checking after a normal drive.

Having the vehicle running idle on the driveway may not be enough. You can check after a drive of around 10 miles. You could go for a little more mile during winter and a little less mile when driving on the highway. When the engine is hot, begin the process of checking and repeat at least three times for accuracy.

Be very careful when checking transmission fluid when hot since both the engine and the fluid is hot. When checking the dipstick, the level of fluid should be in the Hot or Max range. To determine if the vehicle is at its normal operating temperature, look at the temperature gauge on the dashboard. It should read between cold and hot.

Read Also: All You Need To Know About Power Steering Fluid Color

Frequently Asked Questions (FAQs)

Do You Check Transmission Fluid with the Car Running?

Mechanics recommend that you should check the transmission fluid when the vehicle is running. Before you start the process of checking the fluid, park the vehicle on a flat and stable surface, and start the engine. The vehicle should be on parking or neutral mode.

Transmission oil expands with increased temperatures. Therefore, you may not get the correct reading when the engine is off since the fluid tends to drain down in the pan, thus giving the wrong reading. A wrong may cause you to overfill. How long to warm up the transmission fluid, it should take 15 to 20 minutes.

However, some vehicle manufacturers suggest that you check the transmission fluid when the vehicle is not running. Therefore, it is advisable to consult the car owner’s manual first to confirm when they recommend your vehicle.

What Is the Proper Way to Check Transmission Fluid?

The process of checking the transmission fluid is easy and quick. Just make sure that the vehicle is parked on a stable surface and start running when on parking mode. Open the vehicle hood and find the dipstick. It mainly has a red or orange ring on the handle. Remove the transmission fluid dipstick and dry it with a clean cloth.

Insert the dipstick into the transmission fluid and remove it to check the level. Re-insert the dipstick the second time to confirm the reading for more accuracy. If the level is below the add or min mark, then you need to re-fill the transmission fluid. Check the thickness, smell, and color of the fluid. If the fluid has an odor, s thick or brown, then you need to change it.

What are the Symptoms of having Low Transmission Fluid?

Low transmission fluid may cause much damage to your vehicle. It is crucial to keep checking the fluid regularly. You do not have to wait for the stated miles to check the transmission fluid. Some of the symptoms of low transmission fluids are gear slippage, delayed gear engagement, surging transmission, unusual shifts, and trouble shifting gears.

Any of these signs are a warning that the level of transmission fluid is low in your vehicle and needs to be re-filled. You may also note a burning smell or the dashboard warning light may show that the fluid is hotter than usual.

What Happens If You Drive with Low Transmission Fluid?

Transmission fluid helps the transmission gears to run smoothly. Low transmission fluid level may be a result of leaking. In case you continue driving without enough fluid in the transmission system, it may lead to corrosion and wear out of the transmission gears. Eventually, it causes damages that will need costly replacements, rebuilds, and repairs. You can prevent these expensive repairs and replacements by just ensuring that you have the right amount and type of transmission fluid.

What Happens If You Put Too Much Transmission Fluid in Your Car?

Too much transmission fluid leads to foaming, which causes erratic gear shifting. When you overfill the automatic transmission, the fluid foams result in oil starvation, gear shifting problems, and transmission damages.

It is, therefore, prudent to check the transmission fluid regularly to ensure its neither too low nor too high. Transmission fluids expand as the engine heats up. If you check the fluid after a long drive, you may have a high reading, which is an actual sense it is incorrect. This is because the oil may have expanded excessively.

Check Transmission Fluid


Now that you know how and if to check transmission fluid hot or cold, you can comfortably check the transmission fluid. Transmission fluids are an essential part of the transmission system. It does not cost much, but having the right amount could save you severe vehicle damage. Having excess transmission fluids may cause annoying sounds and gear slippage. Low fluids affect and slow down transmission. Always ensure you have also checked the smell, thickness, and color of the fluid as well. In case you notice anything amiss, then it is time to replace the fluid.

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Hi there, I am R. Hasan Tito, a mechanic, and owner of this website. My friend and I created this website to share our knowledge, expertise, and experience with our fellow mechanics' community and car users. I am a specialist and certified automotive mechanic (Both Heavy Commercial and Private Cars). I worked as a Mechanic and Mechanic Supervisor for over fifteen years at Global Rebound Automotive companies - Toyota, TATA, BMW, Nissan, TVs, and Others. Now, I enjoy my new role of leading a team of automotive experts (in their respective fields) and publish new content on a regular basis on my website and social media.

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