How Often to Change Transmission Fluid? A Guide to Recommended Intervals

Your vehicle has several different fluids that do many different jobs for many different parts.

The chances are you’re aware of the workings of engine oil and know that it needs to be changed on a regular basis. But what about transmission fluid?

Just like engine oil, transmission fluid has lubricating and cooling qualities that allow moving components to function and perform as they should. Just like engine oil, it breaks down over time, gets dirty, and needs to be changed. Unlike engine oil, it is also a hydraulic fluid that serves to assist gear shifts and cool the transmission.

Failure to change this fluid when necessary could result in serious engine damage and sizable repair bills. In short, this is one scenario where prevention is way better than cure.

In this guide, we reveal how often you should change transmission fluid, as well as why it is important to do so and what signs will tell you that a change is overdue.

What Does Transmission Fluid Do?

Regardless of whether your vehicle has an automatic transmission or a manual one, this fluid acts as a lubricant. Both systems have moving gears, synchronizers, and bearings. All of those parts move as the vehicle moves forward, and lubrication keeps them moving smoothly.

In turn, this also prevents excess heat buildup. Like an engine without oil, your transmission would overheat from the friction from all its gears, and it could be destroyed.

In short, this fluid is forced through various components within a torque converter with pressure to make your vehicle move faster or slower depending on the amount of pressure the fluid provides.

Why Should You Change the Transmission Fluid in Your Vehicle?

The following list will discuss some of the most important reasons to perform this task frequently.

1. It Deteriorates: Regardless of how good your transmission fluid is, it will break down with usage. Additionally, it gets dirty from gear wear caused by friction. Over time, tiny pieces of metal and contaminants will accumulate within the transmission pan, making its lubricating qualities less effective.
2. Proper Cooling Can Be Prohibited: With this breakdown also comes the inability of the fluid to cool the transmission correctly. The cleaner the fluid, the more it can dissipate heat and prevent damage occurring.
3. Shifting Could Be Affected: Because automatic transmissions rely on their fluids to aid proper shifting, keeping that fluid clean will allow your transmission to function properly. Dirty or old fluid could cause your vehicle to shift erratically, or not at all.
4. Leaking Could Occur: One of the lesser-known transmission fluid duties is that it conditions seals, gaskets, and components within the transmission itself. As it breaks down and gets dirty, its conditioning properties also break down, and leaking could occur as a result.

How Often to Change Transmission Fluid

Technology and variances in how vehicles are designed have contributed to a wide range of recommended transmission fluid change intervals.

Despite this, there are still three main suggested fluid change intervals applicable to most vehicles today.

30,000–60,000 Miles

30,000 to 60,000-mile intervals are still recommended for some vehicles, but are slowly becoming a thing of the past.

This interval is mostly reserved for older vehicles, manual vehicles, vehicles that frequently tow large loads, and other “special use” vehicles like taxis which are subject to unusually extreme driving conditions.

50,000-100,000 Miles

Currently, most manufacturers and mechanics suggest that transmission fluid is changed at some point between 50,000 and 100,000 miles, depending on your vehicle and type of driving.

Even manual vehicles are able to go farther with modern gear oils than back in the day, and even vehicles used for towing are beginning to push the 50,000-mile mark because of more advanced technology and better formulas.

100,000 Miles to Never

The newest vehicles tend to require less frequent changes, with some not even having a section in the owner’s manual for fluid change intervals at all. This is especially common in complex vehicles such as BMW and Mercedes models.

However, most mechanics don’t recommend not having the transmission fluid changed at least once every 100,000 miles. 

Watch the following video for more information:

What Factors Affect How Often You Should Change Transmission Fluid?

There are a few reasons you should consider changing your transmission fluid sooner than suggested, and most of those involve extreme driving conditions.

Vehicles that tow and haul heavy loads consistently should have their transmission fluid changed more frequently. City driving, stop-and-go commuting, and situations where long periods of idling occur will require more frequent changes, too.

This has to do with more frequent transmission gear changes and increased heat within, both of which break down transmission fluid faster than normal.

Extreme climates with large temperature changes can also affect how often you should perform a change. Check transmission fluid levels frequently if this applies to you.

What Are Some Warning Signs That a Replacement Is Overdue?

If you have neglected to perform this task for a while now while you should have done otherwise, your vehicle will often provide you with some obvious warning signs.

1. Your Vehicle Is Shifting Abnormally or Not at All: Just because your vehicle is shifting erratically or not all doesn’t always mean that transmission failure is imminent. A transmission fluid change is often able to rectify this problem, especially if the fluid has degraded and can’t function properly.
2. Your Vehicle Shifts out of Gear: This might be slight slipping or a total loss of gearing. Any abnormal shifting or slipping that occurs should be addressed immediately.
3. Overheating: Extreme driving conditions and not performing frequent enough changes will often result in overheating. This could cause the check engine light to flash or illuminate, which makes it easier to diagnose the issue.
4. Grinding Sounds: If you hear grinding or other noises coming from the transmission, it might be time to replace the fluid.
5. Shifter Doesn’t Feel Right: If your vehicle has a manual transmission and unusual effort is needed to shift or the shifter doesn’t feel right, you might need to get the gear oil changed.

How Do You Know When Your Transmission Fluid Doesn’t Need to Be Changed?

There are several ways to check whether or not a change is actually needed. You can often check the transmission fluid by parking on a level surface and examining the fluid level with your dipstick, much like you would check the oil in your vehicle.

1. Is It Dirty?: If your transmission fluid doesn’t contain visible particles, it is mostly clear, and you can’t see shiny pieces with the fluid, you shouldn’t have to change it.
2. What Color Is It?: Transmission fluid comes in many different colors, but most automatic fluids come in a red or pink color. Manual transmission fluid might be the color of regular oil, but many manual transmission vehicles also use automatic formulas just fine. As long as it isn’t milky, dark brown, or black, you should not have to replace it.
3. Does It Have a Burnt Smell?: One telltale sign that it needs to be replaced is when it smells burnt. If you can’t detect this when checking the fluid, you won’t have to change it.
4. Change Interval Recommended by Your Manual: The manufacturer of your vehicle knows what’s best for it. If it is within normal parameters for a suggested transmission fluid change, you probably won’t have to worry unless your vehicle’s behavior suggests otherwise.

Are There Any Other Tips I Should Know About?

The golden rule for any automotive maintenance questions, vehicle operations, or correct product usage is to reference the owner’s manual. This is especially important if you own a vehicle with a manual transmission.

Manual transmission vehicles can use a variety of different transmission fluids, including automatic formulas.

Your owner’s manual will also tell you the correct interval for the type required on both automatic and manual cars.

Some transmissions have filters that can be changed when new fluid is added. If your owner’s manual specifies to change the filter with the transmission fluid, then it’s important that you don’t forget (or neglect) to do so.

Some of the newest automatic transmissions contain long-life transmission fluid which is reported to last the lifetime of the transmission. 

These transmissions often don’t contain a way to monitor fluid levels except through an OBD II reader (click here for the best OBD II code readers) or transmission scanner.

Also keep in mind that there is no harm in performing this change sooner than what is recommended.

Wrapping It Up

So, as you’ve clearly seen by now, all of this plays a small (but vital) role in keeping your vehicle running smoothly and your driving experience safe.

Changing the fluid at the correct mileage as presented in your owner’s manual will provide you with the best possible experience you can have.

Without proper lubrication, heat dissipation, and shifting ability, your transmission could wear out prematurely or completely fail, leaving you with a hefty repair bill.