A Step-By-Step Guide on How to Change Automatic Transmission Fluid

Maintaining your vehicle’s automatic transmission is crucial for its longevity and performance. One essential aspect of transmission maintenance is changing the automatic transmission fluid (ATF). Regular ATF changes can help prevent costly repairs down the road and ensure your vehicle shifts smoothly. In this comprehensive guide, we will walk you through the step-by-step process of changing your automatic transmission fluid, emphasizing the importance of each step to ensure a successful and effective ATF change.

How to Change Automatic Transmission Fluid

A. Warm Up Transmission

Before you begin the ATF change, it’s essential to warm up the transmission fluid. This helps to ensure that the old fluid drains out more efficiently, taking contaminants with it. To do this, start your vehicle and let it idle for a few minutes. You don’t need to drive the car; simply allowing it to run at idle will heat up the transmission fluid to the optimal temperature for the change.

B. Raise The Vehicle

To access the transmission pan and drain plug, you’ll need to raise your vehicle safely and securely. Use a jack and jack stands or ramps to elevate the front of your car. Ensure it’s on a level surface, and the parking brake is engaged. Safety is paramount during this step, as you’ll be working underneath the vehicle.

C. Check For Leaks

Before you begin draining the old ATF, it’s crucial to inspect the transmission and surrounding area for any signs of leaks or damage. Check for oil spots or wetness around the transmission pan and its connections. If you notice any issues, address them before proceeding. Repairing any leaks is essential to prevent further transmission damage and ensure the success of your ATF change.

D. Locate Drain Plug

With the vehicle safely raised and the transmission warmed up, it’s time to locate the drain plug. The drain plug is typically located on the transmission pan, which is a large, flat metal component beneath the transmission. Refer to your vehicle’s owner’s manual or consult an online resource for the exact location of the drain plug, as it can vary depending on the make and model of your vehicle.

E. Drain Old Fluid

Place a suitable container, such as an oil drain pan, beneath the transmission pan to catch the old ATF as it drains. Carefully loosen and remove the drain plug using the appropriate tools. Be prepared for the fluid to flow out quickly, so ensure that your container can hold an adequate amount. Let the old ATF drain completely.

F. Examine Fluid

While the old fluid is draining, take a moment to examine its condition. Healthy ATF should be red or pink and have a clean appearance. If you notice a burnt smell, discoloration, or the presence of metal shavings, it may indicate transmission problems that require further inspection or repairs. Keep the old fluid for reference, as some mechanics may want to examine it if you experience transmission issues in the future.

G. Remove Old Gasket

Once the old ATF has drained, you’ll need to remove the old gasket that seals the transmission pan. Carefully detach the gasket from the pan using a gasket scraper or a suitable tool. Be cautious not to damage the pan in the process, as it will be reused. If your vehicle uses a reusable rubber gasket, inspect it for any signs of wear or damage. If it’s in good condition, you can clean and reuse it; otherwise, obtain a replacement gasket.

H. Clean Oil Pan

To ensure proper sealing and prevent any contaminants from entering the transmission, thoroughly clean the oil pan. Use a suitable solvent or transmission fluid to clean both the interior and exterior of the pan. Remove any residue or debris, paying special attention to the magnet inside the pan, which is designed to collect metal particles. Clean the magnet and reattach it to the pan.

I. Replace Filter

While the transmission pan is off, it’s an ideal time to replace the transmission filter. The filter is typically located inside the pan and is held in place by screws or bolts. Carefully remove the old filter and discard it. Install a new filter that is compatible with your vehicle’s make and model, securing it in place as per the manufacturer’s instructions. The filter is essential for maintaining proper fluid flow and preventing contaminants from entering the transmission.

J. Install New Gasket

With the transmission pan clean and the filter replaced, it’s time to install the new gasket. If you’re using a rubber or cork gasket, apply a thin layer of ATF to one side to help it adhere to the pan. Carefully position the gasket onto the pan, aligning it with the bolt holes. Ensure it sits flat and evenly on the pan’s surface. This gasket creates a seal that prevents leaks and maintains proper fluid pressure within the transmission.

K. Re-install Drain Plug

Return your attention to the drain plug, which was removed earlier. Inspect the plug for any signs of wear or damage and replace it if necessary. Once the plug is ready, carefully re-install it and tighten it to the manufacturer’s recommended torque specification. Over-tightening can lead to damage, so use a torque wrench if possible to achieve the correct tightness.

L. Refill With New Fluid

Now that you’ve completed the preparatory steps, you can begin adding new transmission fluid. Refer to your vehicle’s owner’s manual for the specific type and quantity of ATF required for your transmission. Use a funnel to pour the new fluid into the transmission through the dipstick tube. This process may take some time, so be patient and avoid overfilling. It’s crucial to use the correct ATF to maintain your transmission’s performance and longevity.

M. Circulate Fluid

After adding the initial amount of new transmission fluid, start your vehicle and shift through each gear, pausing briefly in each one. This will help circulate the new fluid throughout the transmission and ensure that it reaches all components. Recheck the fluid level using the dipstick and add more ATF if necessary to bring it to the correct level. Continue this process until the ATF level is within the specified range on the dipstick.

N. Final Check Of Level

Once you’ve achieved the proper fluid level, turn off your vehicle and allow it to sit for a few minutes. Recheck the transmission fluid level one last time to ensure it remains within the recommended range. If needed, add more ATF to reach the correct level. Replace the dipstick securely, and you’re all set.


Changing your automatic transmission fluid is a crucial aspect of vehicle maintenance that can significantly extend the life of your transmission and ensure smooth shifting. By following this step-by-step guide and paying close attention to each detail, you can perform an effective ATF change, saving both time and money in the long run. Remember to consult your vehicle’s owner’s manual for specific recommendations and always prioritize safety when working under your vehicle. Regular transmission fluid changes will keep your car running smoothly and help you avoid costly transmission repairs.