Is a Transmission Flush Necessary for My Vehicle?

Routine maintenance is the key to longevity for any machine. This statement of fact is especially vital for cars, trucks, and SUVs that navigate the highways and byways across the United States daily. While most of us are pretty good about having our engine oil changed, radiators flushed, and tires rotated, one routine service often overlooked is the transmission flush. In fact, it’s common for many car owners to ask whether a transmission flush is necessary or just a good idea.

Having a transmission flushed every 30,000 to 50,000 miles is crucial, especially if you drive a car with an automatic transmission. Let’s take a look at the top 4 reasons why having your automatic transmission fluid flushed as recommended is indeed necessary.

How Automatic Transmission Fluid Works

There is often some confusion as to how an automatic transmission works. Simply put, an automatic transmission is a hydraulic system that relies on a consistent flow of transmission fluid levels to supply hydraulic pressure in order to operate. Transmission fluid is different than engine oil — it is designed with a specific viscosity and a combination of additives that help reduce expansion as the fluid is heated. This keeps the vehicle's transmission fluid consistent, which permits it to flow efficiently through each hydraulic line inside the transmission. Over time and with continued use, the additives will begin to wear out, which causes the fluid to thin and become more susceptible to expansion due to heat. Dirty transmission fluid needs to be replaced with new fluid for ideal performance.

Why is a Transmission Flush Required?

A transmission flush is similar to other car fluid changes. When you or a mechanic perform an oil change, it’s a rather simple process. They’ll remove the oil pan bolt, remove the oil filter, and let the old fluid drain until it stops flowing. However, it doesn’t fully remove all of the engine oil. Inside the engine block and cylinder heads are a series of galleys that keep a small portion of oil to lubricate moving parts until the new oil is circulated through the engine. An automatic transmission’s fluid is kept inside the hydraulic lines, so it needs to be ‘flushed’ or pushed through the lines to drain effectively. This also serves a secondary purpose. The transmission flush also pushes debris and other small particles that develop from the transmission filter’s worn out fibers.

Here are 4 reasons why this process is so important for those with automatic transmissions:

  1. It extends the transmission lifespan: If the transmission’s internal hydraulic lines are clogged, it can cause inner seals to break, which creates internal leaks and can lead to complete transmission failure. By having the fluid flushed and filters replaced every 30,000 to 50,000 miles, you significantly reduce the potential of damage and can extend its lifespan.

  2. It improves smooth shifting: When transmission fluid is replaced and the fluid is flushed, it improves the efficient flow of transmission fluid throughout the system. The end result is that the transmission will shift smoother.

  3. It is vital to protect warranties: Most new cars, trucks, and SUVs come with a powertrain warranty — which protects the engine, transmission and drive-system components. However, if those systems are not maintained as recommended, it can void most extended warranties and cost you a significant amount of money if you need to replace them.

  4. It can improve fuel economy: A smooth-shifting transmission is also critical for the efficient operation of your engine. If the transmission slips or shifts higher than the engine is set, it can and often will burn more fuel inside the engine than it should. A transmission fluid change can contribute to optimal fuel mileage.

You’ll notice in the information above that we haven’t mentioned transmission flushes for CVT or manual transmissions. These units operate differently and have their own recommended service intervals. The best way to clarify what you should have done for your vehicle is to contact a professional mechanic, your automotive dealership or investigate your owner’s manual for a transmission service maintenance schedule. This will tell you when all the recommended services are required and suggested to keep your vehicle running strong and protect those warranties.


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Recent Transmission Fluid Service reviews

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(1,159)

Rating Summary
1,088
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1,088
41
10
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Peter

25 years of experience
430 reviews
Peter
25 years of experience
Audi A8 Quattro - Transmission Fluid Service - Canyon Country, California
Showed up on time, completed job n a timely manner and shared his knowledge and history of service/repairs on my vehicle.
Honda Odyssey - Transmission Fluid Service - Sylmar, California
Peter is such a nice person with an amazing attitude. We would love to have him as our regular mechanic.

Robert

31 years of experience
626 reviews
Robert
31 years of experience
Honda Accord - Transmission Fluid Service - Santa Clara, California
Robert was punctual with time (infact arrived 15 minutes early) and started inspecting the car and taking photos. I had the appointment schedule for some fluid changes. Based on the condition of the fluids, he recommended that one of the fluids did not require a full flushing out, so he took about an hour off the labor cost for this service, I appreciate that and was done very quickly. He also summarized the overall condition of the car after that. Apart from all that, I noticed that he wasn't wearing a mask. But he maintained the other social distancing protocols.
Toyota Sienna - Transmission Fluid Service - Mountain View, California
Robert was punctual to the appointment. Problem was fixed. Additional services was recommended and scheduled for the next visit.

Theodore

16 years of experience
1382 reviews
Theodore
16 years of experience
Toyota Camry - Transmission Fluid Service - Seattle, Washington
Stand out honesty and professionalism. I have been "using" Theo as my mechanic for about 6-7 years now through YourMechanic - he is hands down the BEST! . This is the second car I have had he has worked on. He saved me a few times before with an older Jeep, now I have an older Camry. For me honesty is 100% most important thing about a mechanic - He is always super honest about what I need and don't need. It's refreshing to hear "your car is in excellent shape, as long as you keep up your maintenances, it will keep going for many years" even when it is 8 years old with 113,000 miles. Today I got tons of maintenance done in preparation for a cross country trip (transmission fluid change, oil change, air filter etc.). I didnt even know my headlight was out. He did all the services booked, then he found fuses blown that I didnt know about, replaced 1 that he had on hand, showed me exactly what I needed to get for a different part, where it was, how I could do it myself, and how to find everything in the car. He communicates very well - nothing is weird or hard to understand, he's totally honest and will tell you "I don't think you need that yet" or "you need to do this - it really is going to break". Before he leaves, he asks you to check everything and make sure everything is okay.. he's all around quality. I have had other mechanics who just wanted to get you our of their space ASAP, he is not like that at all. Easy thumbs up - I recommend him to anyone who asks me about a mechanic.
Toyota Sequoia - Transmission Fluid Service - Bothell, Washington
Theodore once again did not disappoint. We had scheduled a lot of services to be done on our Sequoia and he finished it all within the estimated time. I would highly recommend him.

Robert

4 years of experience
60 reviews
Robert
4 years of experience
Subaru XV Crosstrek - Transmission Fluid Service - Tacoma, Washington
Kept it professional, very courteous and was able to meet time or rather beat time constraints. Always a pleasure working with YourMexhanic.

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