How to Check Transmission Fluid Properly? 7 Easy Steps!

Transmission fluid keeps your car’s gearbox lubricated, cool, and working smoothly. Over time, like other fluids in your car, this fluid can degrade, causing shifting problems and costly repairs. That’s why knowing how to check transmission fluid becomes so important. 

In this blog post, we’ll share 7 simple steps to check the transmission fluid’s level in your vehicle properly. So, without any further ado, let’s get started!

1. Park Your Car on a Level Surface

The first step before checking the transmission fluid level in your car is to park it on a level surface. If your car is parked on a slope, it will affect your readings. You should also use wheel chocks if needed to prevent your car from rolling while you work under the hood.

If you’ve just come back from a drive, then turn off the engine and engage the parking brake properly. Wait a few minutes to let the engine and transmission cool down slightly. 

However, don’t let it get too cold. This is where most people make mistakes. Checking the fluid levels on a slightly warm engine is important because fluids tend to shrink when cold. A slightly warm engine gives you the most accurate results.

Therefore, if your car is parked in the garage, you should let the engine run for at least 5 minutes. This will warm up the transmission fluid to its normal operating temperature, ensuring an accurate reading.

2. Locate the Transmission Dipstick

Once the engine is slightly warm and the car is secure, open the bonnet to access the engine bay. Look for the transmission dipstick. It typically has a red, pink, or yellow handle. 

In most FWD cars, it’s near the front of the engine, close to the transaxle or battery. In rear-wheel drive cars, you’ll usually find it towards the back of the engine, near the firewall.

A transmission dipstick is often labelled and distinct from the engine oil dipstick, which is usually positioned closer to the engine block. If you’re unsure, check your owner’s manual for the exact location based on your car’s make and model. 

If you drive a newer automatic car, it may have a sealed transmission. These transmissions do not have a dipstick at all. In such cases, you need to visit a service centre and check your transmission fluid there. You can’t do it on your own.

Now, let’s assume that you have located the transmission fluid dipstick. You need to clean the dipstick with a cloth after removing it to ensure an accurate, clear reading.

3. Check the Fluid Level

This here is the main step of checking your transmission fluid level. After cleaning the dipstick, insert it fully into its tube and pull it out to check the fluid level. 

Most transmission dipsticks have two markings, “Full” and “Low” or “Add”, to help you determine if the level is correct. The fluid should sit between the two marks; anything below “Low” suggests your transmission needs more fluid.

4. Inspect the Fluid Condition

This is something a majority of people miss. Apart from checking the level, you must also inspect the fluid’s colour and smell for any warning signs. Healthy transmission fluid is usually bright red or pink and has a slightly sweet, clean smell. 

On the other hand, dark brown or black fluid may indicate overheating, oxidation, or contamination inside the transmission system.

If the fluid smells burnt or looks dirty, it’s likely time for a complete transmission fluid change or flush. Driving with bad transmission fluid can lead to friction, wear, and long-term damage that may require expensive repairs.

If the repair cost outweighs the car’s value, you need to consider your options. Sometimes, the smarter move is to sell your car rather than replace the transmission.

Exchange My Car allows you to sell your damaged car hassle-free in the UK. Compare offers from specialist buyers and choose the highest offer you can get from our network. Enjoy free car collection from your doorstep and get paid fast!

5. Add Transmission Fluid if Needed

If the fluid level is below the “Low” mark, it’s time to carefully add more. Always refer to your vehicle’s owner’s manual to identify the correct transmission fluid type recommended by the manufacturer. Adding the wrong fluid can cause slipping, overheating, or long-term internal damage to your transmission system.

To add transmission fluid, place a funnel into the dipstick tube opening to prevent spills. Pour slowly in small amounts, then reinsert and remove the dipstick each time to monitor the changing fluid level accurately. Continue topping up only until the fluid sits between the “Low” and “Full” markings on the dipstick.

You need to avoid overfilling. Adding excess transmission fluid can cause foaming, erratic shifting, and pressure build-up inside the gearbox.

6. Recheck the Fluid After Adding

After adding fluid, wait briefly to let it settle before reinserting the dipstick to check the updated fluid level. The fluid should sit between the “Low” and “Full” marks. This range indicates your car’s transmission now has an optimal amount of fluid.

If it’s still below the required level, add a little more. Then repeat the check after a short wait. Finally, clean the dipstick again and insert it securely back into the tube.

7. Close the Bonnet and Test Drive

Once the fluid level is confirmed, close the bonnet securely. Start your engine and let it idle briefly. Then take a short drive to help the new transmission fluid circulate properly.

Observe how smoothly your car shifts between gears during the drive. Rough shifting, slipping, or strange noises may indicate a problem. If you notice any of these signs, stop driving and consult a professional mechanic right away.

Frequently Asked Questions (FAQs)

Q1: How often should I check my transmission fluid?

You should try to check your fluid level once a year or every two years. However, it slightly varies depending on your transmission type and usage. For instance, automatic transmissions need more frequent checks compared to manual ones. Similarly, if you drive in heavy traffic or use your car for towing, you should check it more often.

Q2: Can I check transmission fluid when the engine is cold?

It’s generally best to check your transmission fluid when the engine is slightly warm. That’s because heat causes the fluid to expand, which gives you a more accurate reading. 

However, some vehicles are designed to allow cold checks as well. That said, it’s always a good idea to double-check your owner’s manual because every car is a little different.

Q3: What colour should good transmission fluid be?

Healthy transmission fluid is typically bright red or pink and has a slightly sweet smell. It should appear clear and smooth, not cloudy, thick, or gritty. 

If the fluid looks brown, dark, or smells burnt, it may signal overheating, contamination, or internal wear. These signs often lead to gear slipping or rough shifting.

Q4: What if my car doesn’t have a transmission dipstick?

It’s possible that your car doesn’t have a transmission fluid dipstick. Some modern cars have sealed transmissions without a traditional dipstick, so you can’t check fluid levels yourself. 

These systems require specialised tools and are best inspected by a certified mechanic during scheduled servicing. However, you should not skip checks at any cost.

While sealed transmissions are designed to be low-maintenance, they can still develop issues if fluid levels drop or degrade. Skipping checks can lead to long-term damage.

Q5: What should I do if the transmission fluid is low or dirty?

If your transmission fluid is low, you need to top it up immediately. Start by using a funnel and the correct type listed in your vehicle’s manual. Pour slowly and check the dipstick each time to avoid overfilling, which can damage the transmission. 

However, if the transmission fluid is dirty, that’s another thing. If the fluid looks brown or smells burnt, it likely signals contamination or overheating. In that case, have it inspected by a professional or replace it completely by draining the old fluid.

Final Thoughts: How to Check Transmission Fluid the Right Way?

Checking your transmission fluid regularly helps you catch small problems before they turn into expensive repairs. A quick check can reveal leaks, contamination, or low fluid that might hurt your car’s performance.

Make fluid checks a regular part of your maintenance routine to keep your car running smoothly, efficiently, and reliably every single day.

However, if your car’s transmission is already failing, it might make more sense to sell your car. Replacing a transmission is an expensive affair, and it often exceeds the car’s value.

If you’re ready to sell your car, Exchange My Car can connect you with the most trusted car buyers in the UK. Enjoy free collection and fast payment while selling your car through Exchange My Car.

Want practical tips to keep your car running smoothly? Head over to our blog for expert advice on maintenance, repairs, and more.