The Sealed Automatic Transmission Flush Deception Revealed by a Mechanic

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.