What mileage should I change my transmission fluid?

There isn’t a universal mileage for changing transmission fluid. For many modern automatics, a typical service interval falls around 60,000 to 100,000 miles under normal driving, but some systems—especially CVTs or heavily driven vehicles—need more frequent changes. Always check your owner's manual for the exact recommendation for your model.

The decision depends on the transmission type, operating conditions, and the specific fluid used. This guide explains the typical ranges, the factors that affect timing, how to spot signs you may need a change sooner, and how to approach the service safely.

Typical intervals by transmission type

General guidelines break down by transmission design. The following ranges reflect common factory recommendations and expert practice, but there are notable exceptions.

• Automatic transmissions with conventional ATF: about 60,000–100,000 miles under normal use; consider 30,000–60,000 miles for severe service (towing, hot climates, heavy traffic).


• Automatic transmissions using synthetic or long-life ATF: about 60,000–100,000 miles under normal use; some manufacturers extend to 100,000 miles or more; always verify your manual.


• CVT (continuously variable transmissions): many experts recommend changing every 30,000–60,000 miles; several modern CVTs specify intervals similar to conventional automatics, but some brands claim "lifetime" with synthetic fluid—still, consider service every 60,000 miles as a precaution.


• Dual-clutch transmissions (DSG, PDK, etc.): intervals commonly range from 40,000–60,000 miles on many models, though some high-performance units may push farther; check the spec for your car.


• Manual transmissions: fluid changes are less frequent, typically around 30,000–60,000 miles for many manuals, though some require longer intervals or only inspection when leaks or shifting problems occur.

In practice, these are guidelines. The exact interval depends on your vehicle’s design and usage, so always follow the owner’s manual or your dealer’s advice, and consider more frequent changes if you drive under harsh conditions.

Factors that affect when you should change transmission fluid

Beyond the base interval, several conditions can push you toward doing a change sooner rather than later.

• Driving conditions: frequent towing, hot climates, city stop-and-go, or short trips that don’t fully heat the fluid can degrade ATF and CVT fluid faster.


• Fluid type and age: synthetic fluids last longer than conventional fluids, but all fluids degrade over time and with heat.


• Fluid color, odor, and contamination: burnt smell, dark or gritty fluid, or metallic particles in the pan signal degradation or contamination.


• Leaks or contamination: a leaking pan gasket or cooler line introduces water or dirt, accelerating fluid breakdown.


• Maintenance history: using the wrong fluid, mixing fluids, or skipping scheduled changes increases risk of transmission wear.


• Transmission design and issues: some sealed transmissions or newer designs may have longer life but still benefit from periodic checks; older or heavily used units may need more frequent changes.

These factors mean your mileage gauge is a guide, not a rule. When in doubt, refer to the manual and consult a qualified technician who can evaluate fluid condition and transmission health.

What to look for and how to prepare for a service

If you’re approaching a recommended interval or you notice shifting issues, here’s how to prepare and what to expect during service.

• Check the manual and listen to the manufacturer: confirm the official interval for your model, including severe-service notes.


• Check the fluid level and condition (if accessible): for many cars, the transmission is sealed and only a dealer can check; if accessible, level should be correct when warm and vehicle on level ground, with fluid smelling clean and not burnt.


• Look for symptoms indicating potential fluid problems: slipping, delays in shifting, harsh or noisy gear changes, overheating, or warning lights.


• Choose the right service approach: drain-and-fill versus full flush. Draining and filling is common and safer on many older or higher-mileage units; a flush can be riskier if the system has varnish buildup or metal debris.


• Plan for a post-service test: take a short, cautious road test to verify smooth shifting and check for leaks.

By following these steps, you can ensure the transmission fluid service supports reliable performance and minimizes the risk of transmission damage.

Summary

The bottom line: there is no one-size-fits-all mileage. Start with your owner's manual, then consider your driving conditions and fluid type. For many drivers with modern automatics, a change every 60,000–100,000 miles is common; CVTs and dual-clutch transmissions often require more frequent attention (30,000–60,000 miles in many cases). If you notice shifting problems or fluid that looks or smells burnt, schedule service promptly. When in doubt, consult a certified technician to assess your specific vehicle and ensure you use the correct fluid type.

How often do I really need to change transmission fluid?

You should change your transmission fluid every 30,000 to 60,000 miles for manual transmissions and 60,000 to 100,000 miles for automatic transmissions, but always check your vehicle's owner's manual for the most accurate schedule. A manual change is recommended sooner for "severe service" conditions like towing, hauling, or frequent stop-and-go city driving. 
General guidelines by transmission type 
This video explains how often you should change the transmission fluid: 59sEveryman DriverYouTube · Dec 8, 2022

• Manual transmission:
  • Normal service: Change every 30,000 to 60,000 miles. 
  • Severe service: Change every 30,000 miles or sooner if you frequently tow, haul, or drive in heavy city traffic. 
• Automatic transmission:
  • Normal service: Change between 60,000 and 100,000 miles. 
  • Severe service: Change sooner, especially if you tow or haul heavy loads. 
• Sealed transmissions:
  • These newer systems are often marketed as "lifetime" and may not have a dipstick, but they can still benefit from periodic checks and fluid changes to prolong their life. 

Other factors to consider

• Owner's manual: Your vehicle's manual is the best source for its specific maintenance schedule. 
• Driving conditions: If you frequently tow, haul heavy loads, or drive in stop-and-go city traffic, you should change your fluid more often. 
• Fluid color: A quick check of the dipstick (if your car has one) can help. Healthy fluid is typically reddish-pink, while dark brown or black fluid with a burnt smell indicates it is time for a change. 

You can watch this video to learn how to check your transmission fluid: 1mBudget MechanicYouTube · Jan 20, 2024

What happens if I never change transmission fluid?

If you don't change your transmission fluid, it can lead to overheating, poor shifting, and eventual transmission failure because the fluid degrades and loses its ability to lubricate and cool the transmission's internal parts. Old fluid becomes dirty and contaminated with debris, which can cause clogs and friction that damage components, while its lubricating and cooling properties diminish over time, accelerating wear and tear.
 
This video explains why changing transmission fluid is important: 1mChrisFixYouTube · Apr 8, 2016
Common issues from neglecting transmission fluid changes:

• Overheating: Old fluid becomes less effective at cooling the transmission, causing it to overheat, especially under heavy loads or in stop-and-go traffic. 
• Poor shifting: The transmission may start to shift roughly, delay gear engagement, or even slip out of gear. This is due to the fluid's contamination and breakdown, which affects its hydraulic properties. 
• Internal damage and clogs: As fluid degrades, it becomes a sludge that can clog narrow passages within the transmission. The debris from worn clutch surfaces also circulates, accelerating wear on other parts. 
• Reduced lifespan and total failure: Over time, the lack of proper lubrication and cooling will cause increased friction and wear, significantly shortening the transmission's life and leading to more expensive repairs or a complete failure. 
• Unusual noises: You may hear grinding or whining sounds, especially during acceleration, as a result of the internal components being poorly lubricated. 

Important considerations

• High-mileage vehicles: In very high-mileage vehicles with no history of fluid changes, replacing the fluid can sometimes cause problems. The old, dirty fluid may have a "gluing" effect on internal components. New fluid can wash this away, potentially causing the transmission to start slipping. 
• Follow the owner's manual: Always check your vehicle's owner's manual for the manufacturer's recommended service interval, as it can vary by make and model. 
• Do not ignore signs: If you notice any of the signs of bad transmission fluid, such as slipping, rough shifting, or unusual noises, it's crucial to have it inspected by a professional. 

What fluids should be changed at 100 000 miles?

At 100,000 miles, you should replace engine oil and filter, transmission fluid, coolant, and brake fluid, as these fluids break down over time and can cause damage to critical components. You should also consider replacing spark plugs and the timing belt, which can fail and cause serious engine damage. 
This video explains why it's important to change transmission fluid after 100,000 miles: 39sCar Care ProYouTube · Sep 6, 2025
Essential fluids

• Engine oil and filter: Oil breaks down and becomes contaminated with metal shavings and carbon deposits, which can accelerate wear on engine parts. A new filter ensures clean oil circulates properly. 
• Transmission fluid: This fluid lubricates the transmission gears. Over time, it breaks down and can become contaminated, so it needs to be flushed and replaced to prevent premature wear. 
• Coolant: Coolant can lose its ability to prevent corrosion over time, even if its heat transfer capability remains. Replacing it at this mileage is crucial for protecting the system. 
• Brake fluid: Brake fluid absorbs moisture, which can lead to corrosion in brake components like the ABS module and calipers. Flushing and replacing it is essential for safety and to prevent costly repairs. 

This video explains why it's important to change brake fluid after 100,000 miles: 1mRQs GarageYouTube · Jul 26, 2022
Other important maintenance

• Timing belt: A timing belt replacement is often recommended around 100,000 miles. A broken timing belt can cause severe internal engine damage. 
• Spark plugs: At this mileage, spark plugs may be worn and should be checked and replaced if necessary. 
• Power steering fluid: If your vehicle has hydraulic power steering, the fluid should be inspected and replaced as recommended by the manufacturer, as it may need service around this time. 
• Differential and transfer case fluids: For vehicles with a 4WD or AWD system, these fluids should also be checked and replaced according to the manufacturer's schedule. 

This video explains why it's important to change fluids after 100,000 miles: 57sTire ReviewYouTube · Aug 28, 2024
Important note

• Always consult your vehicle's owner's manual or a professional mechanic to determine the exact service intervals and fluid types for your specific car. 

Is it okay to do a full transmission flush at 70k miles?

There is no such thing as too often, but every 50-75k miles should be adequate for most any transmission. Don't need a flush, just drain out as much as possibe, replace the filter, and refill equal to what was drained.