Follow our DIY guide to checking and changing your transmission fluid at home.

Transmission fluid is one of your vehicle’s lifelines. It ensures that your transmission stays lubricated and functions properly, avoiding costly repairs down the road. Yet, it’s often one of the most overlooked maintenance tasks.

If you’re wondering how to check your transmission fluid or change it, you’re in the right place. This step-by-step guide from Blain’s Farm & Fleet will walk you through the process to get the job done right.

Why Is Transmission Fluid Important?

Transmission fluid plays an essential role in your vehicle’s performance. It keeps all the moving parts in your vehicle’s transmission system lubricated and cool. Over time, this fluid can break down or become contaminated, which may cause the transmission to work harder than it should. This often leads to things like decreased fuel efficiency, harder shifts, overheating, or even transmission failure.

Thankfully, with a little care and routine maintenance, you can keep your transmission in peak condition for years to come.

What You’ll Need

To check and change your transmission fluid, you’ll need the following tools and materials:

• Transmission fluid (check your owner’s manual for the correct type and quantity)
• Vehicle jack and jack stands or ramps
• Drain pan
• Funnel
• Ratchet and socket set
• Clean rags or shop towels
• Disposable gloves
• Safety goggles
• Flashlight (optional)
• Replacement filter (if necessary)

How to Check Transmission Fluid

Regularly checking your transmission fluid is the first step to ensuring your car is running as it should. Follow these steps to determine whether it needs to be changed:

Step 1: Prepare Your Vehicle

• Park your car on a flat surface.
• Keep the engine running. Most vehicles require the engine to be running and warmed up to accurately check transmission fluid. Check your car manual to confirm.

Step 2: Locate the Dipstick

• Open the hood, and locate the transmission fluid dipstick. It’s typically found near the engine bay. Look for a bright red, orange, or yellow handle labeled “Transmission.”
• Remove the dipstick, and carefully wipe it clean with a rag or paper towel.

If you can’t find the transmission dipstick, consult your owner’s manual.

Step 3: Check the Fluid Level

• Reinsert the clean dipstick fully, then pull it out again.
• Look at the markings on the dipstick, typically labeled as “Full” and “Add,” “Min” and “Max,” or “Hot” and “Cold.” See where the fluid sits to determine if you need to add more. The fluid level should be between the marks, not below.

Step 4: Inspect the Fluid’s Condition

• Check the fluid color. Healthy transmission fluid is typically bright red or pink and free from particles, metal shavings, or dark discoloration. Brown or black fluid means it’s time for a change.
• Next, smell the fluid. A burnt odor is another sign the fluid is overdue for replacement.

How to Change Transmission Fluid

Once you’ve checked the fluid, it’s time to move on to changing it, if necessary. Here’s how to do it:

Step 1: Drain the Old Fluid

• Use a jack to lift your car, and secure it on jack stands for safety. Ensure it is stable before crawling underneath.
• Locate the drain plug or transmission pan. Most vehicles have a drain plug, but some may require you to remove the entire pan. Refer to your owner’s manual, if needed.
• Place a drain pan directly underneath the transmission pan to catch all the old fluid.
• Unscrew the drain plug or pan bolts using a ratchet. Be careful, as the fluid may drain quickly. Allow all the fluid to drain completely, which may take a few minutes.

Step 2: Replace or Clean the Filter

• Some vehicles have a filter that should also be replaced during fluid changes. If your vehicle has a replaceable filter, you can typically find it inside the transmission pan.
• Remove the old filter, and install a new one according to the manufacturer’s instructions.

Step 3: Add New Fluid

• Once emptied, reattach the drain plug or pan. Use a torque wrench to ensure the bolts are tightened to the recommended specifications in your manual.
• Safely lower your vehicle back down to the ground.
• Using a funnel, slowly pour the recommended amount of new transmission fluid into the dipstick tube or designated fill point.
• Start your engine, cycle through the gears, then check the level again. Add more fluid if necessary until it reaches the correct line. Do not overfill, as this can cause issues with the transmission.

And that’s all there is to it! You’ve now successfully changed your transmission fluid.

How Often to Change Transmission Fluid

The frequency of transmission fluid changes depends on your type of vehicle and driving habits.

• Automatic Transmissions: Change the fluid for these about every 30,000 to 60,000 miles. Some newer models use “lifetime fluids,” but it’s still always a good idea to check your owner’s manual.
• Manual Transmissions: Change fluid for these around every 30,000 to 50,000 miles.
• Tough Driving Conditions: If you do a lot of towing or experience lots of stop-and-go traffic, consider changing it more often to prevent excessive wear.

When in doubt, consult a mechanic or refer to your vehicle’s service guide.

Tips for Transmission Maintenance

Regular maintenance helps avoid many transmission-related issues. Here are a few tips to keep your transmission in top shape:

• Stick to the Service Schedule: Check your owner’s manual for recommended service intervals, and follow them closely.
• Use the Right Fluid: Always use the type of automatic transmission fluid (ATF) specified for your vehicle. Using the wrong fluid can cause severe damage.
• Watch for Warning Signs: Look out for symptoms like delayed shifting, slipping gears, or strange noises. These could indicate transmission trouble.
• Avoid Overheating: Ensure your car’s cooling system is functioning well, as overheating can damage the transmission.
• Inspect for Leaks: Check under your car regularly for red or pink fluid puddles, which often signal a transmission leak.

Signs of Transmission Fluid Issues

Spotting trouble early can save you from costly repairs in the future. Watch out for these warning signs:

• Unusual Colors or Odors: Dark or murky fluid and a burnt smell often indicate contamination or overheating.
• Grinding or Delays in Shifting: Rough shifting or delays when changing gears could suggest dirty or low fluid levels.
• Leaks: A red puddle under your car is a clear sign of a transmission fluid leak, which needs immediate attention.
• Overheating: Warning lights and overheating signals can stem from failing transmission fluid.

If you notice any of these issues, act quickly to avoid further damage.

Checking and changing your transmission fluid might seem like a daunting task at first. But with the right tools and guidance, it’s easier than you might think. Regular maintenance of your transmission fluid helps ensure your vehicle runs smoothly, avoids costly repairs, and keeps you safe on the road.

If you’re unsure about any step, don’t hesitate to consult your local mechanic or refer to your car’s owner’s manual. The skilled, trained mechanics in our Automotive Service Centers are always happy to help.

For more how-to guides like this one, check out our other Auto Maintenance articles.