Blackstone Labs says for non-high-temperature usages, just look out for ATF leaks and let the fluid go lifetime.

Transmission oils are mainly used as a hydraulic fluid to shift the gears though an ingenious invention called the valve body. This is like a circuit board that uses oil rather than electricity, and apparently the cleanliness of the oil doesn't much affect its operation. Sure the oil also lubricates the gears, but as far as an oil's jobs go, that's one of the easiest things for it to do. The oil really doesn't even have to be very clean to do that job well. So if the cleanliness of the oil isn't that critical, then lifetime transmission oils start to make sense.

It has been our experience that what kills most transmissions is heat. If the oil gets too hot it actually loses its viscosity and is no longer able to lubricate properly, which in turn causes more heat and eventually a total failure. What's the number-one cause of the oil becoming too hot? Oil volume lost due to a leak. With less oil circulating through the system, the remaining oil is stretched thinner (so to speak) and gets hot faster. It’s a vicious cycle, one to avoid if possible.

So in closing, if you have a “lifetime transmission oil,” rest easy — there is probably no need to worry about changing it. You'll likely get sick of looking at the vehicle before the tranny dies. However, if you notice your transmission starting to leak oil, that's the time you'll want to have it fixed because its lifetime will quickly expire if you don't. Just be sure they put the right oil back in! "

Blackstone Labortories, Inc. 2019

 

Define lifetime.

 

Ask Blackstone Labs that question!

 

lol

If a transmission dies the fluid did last a lifetime. Lifetime of the transmission.

 

Fun fact: most parachutes come with lifetime warranties...

 

Lifetime of a typical car before it goes to the scrap yard. 13-17 years.

my old mans Es300 is 24 years, on original ATF fluid. Shifts smooth as silk. Never had to top up. the Fluid is black 😀

 

Yeah, I'll go with Blackstone and the OEM on this one.

 

You could say 'Lifetime' is the Life Expectancy

I would surmise that a typical well-built automobile has a life expectancy of 12-16 years or 180k-250k+ miles with regular maintenance as recommended* by the car maker.
* Lexus does not recommend servicing the transmission

 

Bingo!

 

Ok one car made it. How many other ES300's 24 years old, did the Transmission go out on? Fair to do a real comparison? lol?

 

Well, Aisin seems to disagree... But what do they know, they only make the transmissions, right?

 

But Lexus DO recommend servicing/changing fluid on your transmission.
90k km fluid change on my GS250 if towing.
Literally says “if towing”. How much towing is needed for the oil change to be a requirement? Doesn’t say.
Loose defintion.

There are many transmissions out there with 300k miles on stock oil that still works.
There are many transmissions out there with 30k miles that’s broken.
I just change my oil. Why make such a big deal out of it? 90k km trans oil change, just what the service schedule says.
If it’s necessary or if it would work just aswell without the oil change is something you’ll never ever get to know. But what I do know for a fact that right here, right now, after an oil change my trans still works.
And that’s good enough for me.

And just like I replied to you in the other thread, “Lifetime” without a definition can be just about anything.

 

Just like how BMW states “lifetime” but ZF says 60k km.
But ZF only builds the transmission so wtf do the know?
Ofcourse this leads to transmission troubles. On the 6HP it mainly led to the lockup failing to lockup so it would lockup, release, lockup,release over and over again for all eternity.
Mine had failed converter lockup but also had a shudder that I believed to be a clogged solenoid for oil pressure, felt like oil pressure spikes. Sure enough, an oil change (and concrete change……) sorted out that shudder aswell.

But to give it a twist, ZF says you must use their own oil in the 6HP transmissions when a Ford 6r80 (which literally is a ZF 6HP) uses Mercon LV.

 

I'm a believer that all fluids need changed. Car manufacturers play games with "Lifetime" fluid and it helps them when media looks at cost to own. Take a look at other parts of the world where cars are sold and look at their manual. My LX has the same recommendation; however, if you pull up the middle east countries they recommend changing it. Same with oil weight. We get recommended a weight that is not necessarily best for your car, but helps a company meet their fleet wide MPG goals. Changing fluids are cheap if you can DYI. A little more expensive to find a Indy shop, but cheaper than replacement. To each is their own.....I'll change my fluids.

 

Lifetime? Unless it is specifically defined by Lexus and they guarantee the Aisin transmission will last that long, lifetime is meaningless.
Actually, it is at best misleading and more likely dangerous because it is undefined.

I find it odd that some make up their own definition and then expect it to be Lexus' definition. Especially when the manufacturer, which is partially owned by Lexus, states otherwise.