Modern transmissions come with "lifetime" fluid.

The manufacturer often has no recommended interval for ATF drain and fill or flush.

The dealer may recommend ATF change or flush at ~40,000 miles.

If an owner wants to get 200k+ miles out of a vehicle (or the power train at least), is it really possible with never changing the ATF? What mileage interval should it be changed?

"Lifetime" fluid is good for the lifetime of the transmission. So when it fails, its lifetime is over.

Ask your dealer what "lifetime" guarantee they make on the lifetime of the transmission and they'll tell you the vehicle's warranty years/mileage. So if you want your transmission to only be guaranteed for 60,000 or whatever the warranty is then don't change your transmission fluid.

Personally I'd recommend changing the transmission fluid at 60,000 miles and then every 30,000 thereafter. And that's a drop the pan fluid change. Never flush! Some people may tell me that's too often but fluid is a heck of a lot cheaper than transmissions.

Toyota says 60k under severe conditions such as towing. No interval under normal conditions. So I change mine at 120k.

You just have to define "who's lifetime?". Is it the lifetime of the trans? Yeah ok. When it dies prematurely it's lifetime is over.

Is it the lifetime of the car? Probably not. Most cars today are capable of 300k miles. A transmission that has never been serviced won't do that, just like the engine wouldn't if you never changed its oil.

Lifetime of how long you'll own the car? Who knows. Do you trade up every year and keep snowballing that debt?





Bottom line is that "lifetime" transmission fluid is a lie. It has a life span just like everything else and if you never change it, you won't like the outcome.

I do it at about 75k on my 4R. I don't tow. It's one of those things that once you pass a certain threshold, there's no going back.

I bought a lawnmower last year that the manual said you never have to change the oil. Pretty amazing what they're able to do these days. (sarcasm)

Didn't manufactures go this way when owners started to add too much fluid or the wrong fluid? It's not as easy as changing oil so they took away the trans dip stick and I guess left it up to the dealers to service. Then the dealers didn't want to mess with it so they labeled it lifetime.

It's not that hard to drill a couple of strategic holes and thread them for plugs, or weld on a bung for a plug.

Here's a good watch.

I should probably look in to this for my 2013 f150 with 85k on the clock. I drive it so infrequently these days I sometimes forget to think about things more than oil changes.

Sea Speed said:

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I should probably look in to this for my 2013 f150 with 85k on the clock. I drive it so infrequently these days I sometimes forget to think about things more than oil changes.

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6R is fairly easy to service. I usually extract as much as I can from the fill hole before i drpp the pan.

It's at least guaranteed for the warranty period, so I think that's a starting place for when to have the fluid changed.

There are a lot of power trains with 5y/60k mile warranties. So 60k seems like a good starting point.

I have a Mazda and I know one dealer recommended a flush every 40k.

Why is flushing frowned upon? A lot of dealers advertise it, and not a drain and fill.

bmks270 said:

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It's at least guaranteed for the warranty period, so I think that's a starting place for when to have the fluid changed.

There are a lot of power trains with 5y/60k mile warranties. So 60k seems like a good starting point.

I have a Mazda and I know one dealer recommended a flush every 40k.

Why is flushing frowned upon? A lot of dealers advertise it, and not a drain and fill.

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Because it's a huge profit generator and 90 percent of the time is a 3rd party flush machine that uses regular ATF and you add the additional additives to make it work in your transmission. Also the filter isn't touched.

Lifetime transmission fluid means nothing more now than it did 30 years ago. It'll last until the transmission conks out, which is a lot sooner than it would have been if it was maintained.

Don't flush it knocks everything loose at once and bad things tend to happen. Went through this with the wife's Diesel Cruze that Chevy said was a lifetime fill. That meant it was good until the warranty was over, I noticed a lot of people complaining about issues and the fix was a replacement transmission.

I switched it over to Amsoil (actually cheaper than the Chevy fluid) drained and filled 3 times over a week. After that it was a drain and fill about every 30000 miles. I ordered the fluid to do it again this fall, but the car got totaled before I got to it.

FWIW, my company F350 which tows heavy often and is over weight from time to time has lifetime fluid in it and they haven't seen the need to change it after 150000 miles. The company probably has close to 1000 pick ups and I haven't seen a transmission in the shop in 4 or 5 years.

I thought part of the reason manufacturers eliminated the dip stick was so that the transmission would be able to work at higher pressure and also less loss of fluid from vaporizing. Also keeps out contaminates.

Or something like that. No idea really.

MouthBQ98 said:

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It's not that hard to drill a couple of strategic holes and thread them for plugs, or weld on a bung for a plug.

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Uh yeah it is.

bam02 said:

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MouthBQ98 said:

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It's not that hard to drill a couple of strategic holes and thread them for plugs, or weld on a bung for a plug.

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Uh yeah it is.

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Uh, no it isn't.

Y'all can plug your bungs all you want, but nothing is going near mine

Around 2015, Toyota started including an "ATF Thermal Degradation Estimate" that can be accessed via Tech Stream or OBDII apps (OBD Fusion with their Toyota enhanced PIDs).

It's essentially an oil life indicator I assume based on number of engine starts/stops and transmission temperature monitoring.

The number ranges from 0 to 65535. Although not in the owners manual, the Toyota factor service manuals say to change the fluid if it goes above 50000.