Whether you're maintaining a single vehicle or a fleet, regularly flushing and replacing transmission fluid helps extend the lifespan of your transmission.
Note
Always check your owner’s manual for the correct type of transmission fluid and recommended change intervals.
In this guide
What to Expect
- Time Needed: 45-90 minutes
- Difficulty: Moderate
- Average Cost: $58
Source: 2025 Fleet Benchmark Report
What You’ll Need
New transmission fluid (check owner’s manual for type and quantity)
Drain pan
Socket wrench set
Funnel
Transmission filter (if replacing)
Gasket or sealant (if required)
Shop rags & gloves
How to Flush & Replace Transmission Fluid
Step 1: Warm Up the Transmission
- Start the vehicle and let it idle for 5 to 10 minutes to warm up the transmission fluid.
- Turn off the engine and engage the parking brake.
Step 2: Drain the Old Transmission Fluid
- Locate the transmission fluid pan under the vehicle.
- Place a drain pan underneath and remove the drain plug using a socket wrench.
- Allow all fluid to drain completely.
Pro-tip
Don’t see a drain plug? Some vehicles require removing the entire transmission pan to drain the fluid.
Step 3: Replace the Transmission Filter (If Required)
- If your vehicle has a serviceable filter, remove the bolts securing the transmission pan.
- Carefully lower the pan and remove the old filter.
- Install the new filter, making sure it’s seated properly.
Step 4: Reinstall the Transmission Pan & Add New Fluid
- Clean the pan and gasket surface before reinstalling.
- Tighten the drain plug or pan bolts to the manufacturer’s torque specification.
- Use a funnel to add the correct amount of new transmission fluid through the dipstick tube or fill port.
Step 5: Check Fluid Levels & Test Drive
- Start the engine and shift through all gears while parked to circulate the new fluid.
- Check the dipstick (if applicable) to ensure fluid is at the correct level. Add more if needed.
- Take the vehicle for a short test drive and monitor for smooth shifting.
Avoid These Common Mistakes
- Using the wrong type of transmission fluid. Using the incorrect fluid can lead to slipping gears and damage. Always check the owner’s manual to ensure you’re using the right type.
- Overfilling or underfilling the transmission. Too much or too little fluid can cause shifting issues and transmission overheating. Always fill to the recommended level.
- Skipping the filter replacement. If your transmission has a serviceable filter, skipping this step can leave contaminants in the system, reducing the effectiveness of the flush.
Track service histories across all fleet assets
Fleetio makes it easy to log transmission fluid changes, track service history, and set automated maintenance reminders, so every vehicle stays road-ready.
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FAQs
How often should I flush and replace my transmission fluid?
Most manufacturers recommend every 30,000 to 60,000 miles, but some transmissions use lifetime fluid that lasts longer. Fleet vehicles may require more frequent changes.
What are the signs that my transmission fluid needs changing?
Common signs include delayed or rough shifting, slipping gears, dark or burnt-smelling fluid, and transmission overheating.
How much does a transmission fluid change cost?
A DIY fluid change costs $50 to $150, while a professional flush typically costs $150 to $300, depending on the vehicle and shop.
Can I change my transmission fluid myself?
Yes, but some vehicles require special tools or professional service. If your transmission doesn’t have a dipstick or drain plug, consider having a shop perform the service.
What happens if I don’t change my transmission fluid?
Old fluid can lose its protective properties, leading to hard shifts, overheating, and premature transmission wear. In extreme cases, it can cause transmission failure.
