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The Sealed Automatic Transmission Flush Deception Revealed by a Mechanic

To flush or not to flush---that is the question a former car dealer and now-popular YouTube channel mechanic answers as he explains the sealed automatic transmission deception to car owners and why spending $200 in fluid is a much more sensible approach than spending six to eight thousand dollars for a new transmission.

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The Missing Dipstick Mystery

Have you ever inspected a recently used car or a new car to buy, but could not find the transmission dipstick and did not want to say anything at risk of sounding like a rube? You are not alone. Nor are you alone with many other car owners who believe the dealership manager or garage tech when they tell you that changing the transmission fluid in your vehicle is no longer needed.

As it turns out that missing dipstick and claim that your new car transmission is “filled for life” (as ambiguous as the old “guaranteed for a lifetime” claim) are all due to a change in an automotive industry that is increasingly installing sealed automatic transmissions into new cars.

Why? That’s a good question, but one without an easy or perhaps even truly honest answer.

The automotive makers extoll the virtues of a sealed automatic transmission in that it:

• Will no longer require the past 50,000 to 60,000 mile oil check and change requirement.
• Will provide customers with what they want by making vehicles almost entirely maintenance-free.
• Will save on significant oil production and disposal.
• Is totally unnecessary due to the advances made with synthetic oil.

Do Sealed Automatic Transmissions Last Longer?

This all sounds good on paper, but are sealed transmissions really any more durable and long-lasting than the non-sealed transmissions? A search of this question yielded at least one common theme amongst mechanics and car experts---that they do not believe this to be totally true.

What is undeniably true is that when it comes to transmissions of all types is that it’s really about the conditions a transmission is exposed to---not so much the miles.

In fact, some auto experts have pointed out that cars with sealed automatic transmissions actually have caveats in small print recommending that changing the fluid in a sealed automatic transmission may be necessary by 50,000 miles when exposed to dusty conditions or used for off-road driving and/or towing.

In other words, the overall stresses placed on a transmission are widely different when comparing a car that is used to tow a trailer as opposed to the same model car that never pulls more than its own weight and that of its passengers.

Towing a trailer greatly increases the temperature of the transmission fluid and thereby shortens its life. In addition, the wear on the gears and clutch plates are also under the added stress of towing and thereby also experience increased wear and tear that will shorten the life of a transmission.

All of this wear of parts releasing metal particles that exacerbate further wear, and the chemical breakdown of the transmission fluid that results in decreased lubrication is undeniable; however, also invisible since with a sealed automatic transmission, you no longer have a dipstick or in some cases even a drain plug with which to collect a sample of the oil to have some idea or indication of the actual condition of a transmission.

And who stands to benefit from that?!

I will leave you to ponder this question over and the implications of how car maintenance is further removed from car ownership---and in some cases even in a service center’s or garage’s ability---toward keeping your car running well as long as possible.

Here is a highly recommended Toyota Maintenance YouTube channel where a popular YouTube mechanic explains his views on why sealed automatic transmissions are not really “sealed for life” as the claim appears to promise; but rather, they do need to be flushed at a cost of $200 in fluids plus labor, over the cost of $6,000 to $8000 for a new transmission.

Flush or Not Flush---Sealed Automatic Transmissions

More Evidence of Sealed Automatic Transmission Deception by the Automakers?

Before you consider flushing out your fluid or having someone else do it to a sealed automatic transmission, you need to be aware that along with the advancement of a sealed transmission the car owner bought with his car, it also came with an increasingly difficult-to-service piece of machinery that requires specialized knowledge that might be unavailable to the owner or the garage.

Here’s a YouTube video by the same mechanic who demonstrates how the fluid is flushed in a sealed automatic transmission and why this can be a near-impossibility for even an experienced shade tree home mechanic or some commercial garages.

Toyota Sealed Automatic Transmission Maintenance Service

And Finally…

If you have any experiences dealing with a car that has a sealed automatic transmission, please let us know about what you found with yours in the comments section below. We greatly appreciate your sharing of your knowledge with others who may experience problems with their transmission or have questions about this type of transmission.

COMING UP NEXT: How to Service Your Automatic Transmission Yourself

Timothy Boyer is Torque News automotive reporter based in Cincinnati. Experienced with early car restorations, he regularly restores older vehicles with engine modifications for improved performance. Follow Tim on Twitter at @TimBoyerWrites for daily automotive repair and maintenance news.

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Dave Przy (not verified)    August 3, 2021 - 11:56PM

2016 Ford Escape with towing package. Easy to drain, refill, (about 1/3rd of total fluid) but checking level was problematic. Better to measure what you drain for refill. Had to remove front wheel then redevelop car to let an access plug spew our excess until correct level.

Daryl Rutschmann (not verified)    August 4, 2021 - 8:48AM

I’m contemplating using my 2007 4Runner Sport (V8, full time 4wheel drive) with 150,000 miles to tow a small camper. Vehicle has been owned by me since new. Nearly always garaged, always maintained by local Toyota dealer per standard maintenance schedule. Should I be concerned re aging parts, hoses, etc? Is a remedy cost effective? What about transmission issues? Anything I should be aware of, take care of before using this to tow vehicles?

Timothy Boyer    August 5, 2021 - 9:22AM

In reply to by Daryl Rutschmann (not verified)

Well...after 150,000 miles you can expect to find at least some issues that may need taking care of just because of aging alone. For example, if I had the same vehicle and were planning a trip towing a camper, as a minimum for safety's sake for towing I would make sure the suspension is good and the protective rubber boots covering all joints and the axles were not rotted off or seriously cracked open. Since towing puts a lot of stress on a transmission, you need to find out if the fluid has ever been changed. Have the wheel bearings checked along with the brakes. Tires should be relatively new---you do not want a blowout while pulling something. Find a mechanic you trust and ask them to give it a once-over is best. And most important of all---make sure you are not exceeding the vehicle's towing capacity, which is one of the biggest mistakes towing drivers make.

Robert Thorne (not verified)    August 5, 2021 - 8:25AM

I have a 2011 Chevy Cruze with a sealed transmission. When I first bought the car, I was led to believe that I could not service the transmission myself, but had to take it to a mechanic. That turned out to not be true. In fact, not only could I replace the transmission fluid myself, but that after 120,000 miles, it is recommended. Doing it myself cost approx. $100. Of coarse, the professionals charge about $250. So saving some money was nice. The caviat is that changing the fluid myself isn't the same as a flush. The process of pushing out the old fluid under pressure is much more thorough. So, change the fluid every 50000 miles after 120000. And as long as you aren't finding any debris in the fluid, you're good to go.

Timothy Boyer    August 5, 2021 - 9:27AM

In reply to by Robert Thorne (not verified)

Good point---there is a difference between draining and refilling versus actual flushing. I believe the mechanic's method he mentioned was draining and refilling multiple times with new fluid each round, hence his comment about buying a lot of fluid for the job. Thanks for the input.

Timothy Boyer    August 21, 2021 - 10:16AM

In reply to by Robert Thorne (not verified)

Yes, most car owners are under the impression that they cannot do the fluid change themselves, but as you pointed out it is still a doable car maintenance task that will save significant money. Good point on that a flush is not always necessary. Thanks for the input.

Steve Baab (not verified)    August 21, 2021 - 12:17AM

As a retired lifetime mechanic..i just warm it up & drain & refill my '05 matrix awd(90k)&'04 tacoma 4x4(190k) every 2 years.. I bought the tacoma used so i flushed & pulled pan at 140k...use Castrol import problems..p.s..i drain & refill coolant same time..yea..its all spotless & trouble free..

Zelma Owens (not verified)    December 20, 2021 - 8:24AM

Own 2013 Toyota Sienna minivan have 239 thousand miles on it has a sealed automatic transmission front wheel drive have never had it flush because I did not see any recommendation for it in my owner manual my trac and engine light came on had it check report say it were transmission shift solenoid and flush transmission but they told me at maintenance shop not to flush at this mileage mostly likely start problems what you thank confuse .

Michelle Jeffery (not verified)    June 27, 2022 - 7:22PM

In reply to by Zelma Owens (not verified)

I was hoping someone in the know could tell me if I had my sealed automatic transmission flushed and devices should they have replaced the filter?

Mark (not verified)    December 6, 2023 - 10:36AM

Just had my 2013 Hyundai Elantra in the shop due to the car not wanting to go in reverse. Found that squirrels had been chewing on the wiring harness and messed up the electronic transmission. After the $510.00 to replace the connector, I asked the shop to change my transmission fluid on a car with 246,000 miles on it. They recommended against it, because if it had never been changed, it might cause more harm than good! I’ll update if the car sinks on me before 300,000. If it makes it past that, I’ll call it the best investment I ever made and buy another one:-)