How to Change Transmission Fluid Yourself
When it comes to DIY car maintenance, oil changes get all the attention. But changing your transmission fluid is just as important. People often ask, “Is changing transmission fluid easy?” or “Should I change my transmission fluid myself?”
If you’re reading this page, you’re probably considering doing the job yourself. One thing to keep in mind is that having a dealer or repair shop perform a transmission fluid change typically costs between $282 to $343. If you have about an hour and are comfortable with basic vehicle maintenance, this is a task many DIYers can handle themselves.
A transmission fluid change is a cost-effective maintenance task well within the reach of regular folks. It protects your transmission and keeps your vehicle running smoothly. Some people call it a transmission oil change, but the process is the same. If you want to know how to change transmission fluid, this guide helps.
Let’s go through the simple steps you need to change the transmission fluid yourself. Before we get started, let’s tackle some common questions.
Is transmission fluid the same as oil?
While both are oils and lubricants, engine oil is primarily for the internal combustion engine and transmission fluid is for the steering system. They should never be used interchangeably.
What happens if you don't change transmission fluid?
Over time, transmission fluid becomes dirty and less effective. It won’t lubricate the transmission as well, leading to increased heat, friction and engine wear.
How often should you change transmission fluid?
Transmission fluid can last much longer than motor oil. For manual transmissions, you should change the fluid every 30,000 to 60,000 miles. Automatic transmissions should be changed every 60,000 to 100,000 miles. But it’s important to check your transmission fluid periodically in case of leaks — and always refer to your owner’s manual for specific guidelines for your vehicle.
A standard drain and fill replaces about 40 to 60 percent of the total fluid. The rest stays in the torque converter and cooler lines. A transmission oil change at regular intervals prevents costly repairs. Knowing when to change transmission fluid depends on your driving habits and vehicle type. Regular transmission fluid replacement keeps your transmission running smoothly for years.
What are the symptoms of low transmission oil? (Or that your fluid needs to be changed.)
You’ll want to keep an eye, ear and nose out for signs such as these:
- Dirty transmission fluid (good fluid is clear or pink; old fluid will be deep red or brown)
- Burning smells
- Transmission slipping
- Whining or grinding sounds
- RPM spikes
- Vehicle can’t shift into reverse
- Engine running hot
What is the difference between a transmission fluid change and a transmission flush?
A transmission fluid replacement can be done two ways — by drain and fill or by flush. A transmission fluid change drains the old fluid and replaces it with fresh fluid. A transmission flush uses a machine to push new fluid through the entire system. The flush replaces up to 95 percent of the old fluid. The change replaces about half.
For most DIYers, a drain and fill will do the trick. It is simpler and gentler on the transmission. A flush can dislodge debris in high-mileage vehicles. That can cause more harm than good. Not sure where is the transmission fluid pan? Your owner's manual will show you. Unsure when to change transmission fluid? Check your owner's manual for the right method.
Method | Fluid replaced | Typical cost | Best for | Risk |
Drain and fill | ~40–60% | $40–$100 (DIY) | Routine maintenance, high-mileage vehicles | Low — gentle on the transmission |
Flush | Up to ~95% | $150–$200 (shop) | Severe contamination, thorough cleaning | Can dislodge debris in high-mileage units |
Now that we’ve covered the questions, let’s get into it.
Time
Allow about 1 hour
Tools
- Socket wrench set
- Drain pan to catch the used fluid, plus a container (see supplies)Funnel
- Rubber or latex gloves (to keep fluid and grease off your hands)
- Safety goggles
- Car jacks
- Jack stands or ramps, depending on how much you need to raise your vehicle
Supplies
- New transmission fluid (check your vehicle’s owner’s manual for specifics or check The Castrol Motor Oil & Fluid Finder)
- New transmission filter
- Container with lid for the used fluid (so you can recycle it)
- Rags for cleanup
10 steps to change transmission fluid
Once you have all your tools and supplies, you’re ready to get started. So let’s do this.
Step 1: Get your car ready and check the transmission fluid
Before you raise your vehicle, start the engine and let it run until it’s warm. For safety, park on a level surface and set the parking brake. Find the transmission fluid dipstick (it’s usually red or orange), pull it out, wipe it with a clean rag and reinsert it. Pull the dipstick again and check the level and color. Dirty fluid will be dark red or brown.
Step 2: Raise your car
Make sure you turn off the engine and let it cool for five to ten minutes. You’ll need to get access from underneath. This is where the car jacks and jack stands or ramps come into play. Never rely on just a jack to hold up your car when you’re going to be working underneath.
Step 3: Locate the transmission fluid pan and check for a drain plug
For most front-wheel or four-wheel drive vehicles, you’ll find the pan on the left or right side of the engine. On rear-wheel-drive vehicles, it’s typically located beneath the center console area.
Next, check to see if your fluid pan has a drain plug. If your car does not have a drain plug (and unfortunately, most do not), you’ll need to take off the entire transmission pan. But read Step 4 before doing so.
Step 4: Get ready to drain the transmission fluid
Set up your drain pan to catch the fluid. Make sure that it’s wide enough and in the right spot to avoid a messy spill. Put on your gloves and safety goggles. When you’re sure that your drain pan is lined up, you can prepare to remove the plug or the entire fluid pan.
To remove the plug: loosen, but hold in place.
To remove the entire fluid pan: remove all the bolts (usually 6 – 8 of them)
Be careful, once you fully release the plug or remove the pan, the fluid will start pouring quickly. Letthe old oil drain until it has slowed to a drip. Once the fluid has finished draining, wipe down yourdrain plug and/or the pan and reattach.
Step 5: Check the old fluid for debris
It’s not unusual to find small metal shavings in the old transmission fluid. But if you see metal shards that are large enough to pick up, you have a problem. You’ll want to stop using the vehicle and have a mechanic inspect the transmission for damage.
Step 6: Inspect the transmission fluid filter
In most situations, the filter does not need to be replaced. But you’ll want to inspect it for any cracks or leaks. The filter will be attached to the transmission with some clips, bolts or the filter’s O-ring gasket.
If you do need to replace the filter, simply remove it and wipe down the area where the filter was attached. Before you attach the new filter, you’ll need to quickly lubricate the O-ring gasket. Dip your gloved index finger in some of your new transmission fluid and apply a light coating. Then install the new filter and reattach the bolt. Make sure it’s secure, but don’t overtighten.
Step 7: Reattach the transmission fluid pan
Skip this step if you only had to remove the drain plug. Make sure the filter is properly attached. Wipe down the pan and bolts. Then line up the pan and hand tighten the bolts. Next, use your socket wrench to fully tighten. Avoid over tightening so you don’t damage the pan or the bolts.
If your owner’s manual does not have a recommended torque, you’ll just want the bolts to be screwdriver tight.
Step 8: Refill with the new transmission fluid
Knowing how to fill transmission fluid properly prevents overfilling and is simple using a long-neck funnel. Pour the new transmission fluid into the dipstick tube. Check your owner's manual for the correct fluid type and capacity. Pour slowly to avoid spills. First time putting transmission fluid in a car? Take your time and check the level often.
Step 9: Inspect for leaks, then check the fluid level
Start your engine and let it run for a few minutes. This will help the new fluid circulate. Check underneath your car to make sure there are no leaks.
Then open your hood to check the fluid level. Remove the dipstick and wipe away the fluid with a rag. Reinsert the dipstick, then remove again to check the level. It should reach the “full” mark at the tip. If not, slowly add a little more fluid and recheck.
Step 10: Properly dispose of that old transmission fluid
Never pour the old fluid down the drain or into a drainage sewer. Instead, you’ll want to pour it into a container with a lid. Many auto parts stores will accept and recycle used transmission fluid. You can also contact a local recycling facility or your town to see if they will accept it.
That’s it!
You just saved yourself up to $250. And like most things, changing your transmission fluid gets easier every time you do it. You’ll be a pro in no time.
