pdxABC

I own a 2015 ES350 sedan with 45K miles, still under Certified coverage. I took it to one Lexus dealer (closer to me than the dealer where I bought the car) and they said that my transmission fluid was dirty and that the transmission system needed to be flushed and the new transmission fluid then added. Then I took my car to the Lexus dealer where I bought it, and they said that my transmission was a closed system and that they don't flush or replace the transmission fluid (for the life of the car, as I understand it.

So, presumably, one of the dealers is right and the other is not?

I'm looking for some insights into what the correct answer is.

Thank you for your insights!

LeX2K

I've seen Toyota Camry's have their transmissions fail at 120,000 miles, the "lifetime" fluid was just that too bad the lifetime was so short. On your car I'd replace the fluid every 35,000 miles.

bc6152

You can find answers and opinions, many, many posts regarding this contentious subject if you do a search. Some say change it and Toyota says never change it... No right or wrong...

LeX2K

Seattle SCone

It's a matter of how long you intend to use the vehicle. Lexus can state it is a lifetime transmission fluid and be truthful, provided you understand "lifetime" to be 7 to 10 years. Indeed, with a 70 to 100K mile lifespan, the original ATF is likely to allow the transmission to survive. Beyond that span, it's not the original owner's nor Lexus problem if the transmission fails beyond its "lifetime." A sealed ATF may allow the ATF fluid to last a bit longer due to reduced exposure to atmosphere via the fill tube, but still gradually degrades the ATF through heat and buildup of degradation products and mechanical debris. Lifetime is not forever.

Once a transmission begins to wear due to loss of ATF protection and lubrication, it's too late to save the transmission. The damage has already been done. It's after the owned "lifetime." so the manufacturer need not stand behind the product. The car is likely to have already passed to another owner by then. So it's nobody's responsibility at that point. Changing the ATF after damage has occurred may mean the transmission will stop working. Changing ATF before damage, minimize transmission wear.

On the other hand, if you are a later owner or someone who intends to keep the vehicle for a prolonged time, the strategy changes for prolonging AT lifespan. The game changes from "how long can I go before this breaks" to "how can I make this last as long as possible." In that scenario, periodic changes of the ATF before the ATF degrades is prudent. ATF fluid replacement will likely prolong AT lifespan beyond simply keeping old, degraded ATF in the system. So, it depends. Are you planning to keep the car a long time or going to get rid of it and don't care whether you are screwing over the next owner.

Both Lexus dealerships are "correct." The first is doing the right thing for someone who wants the car to last as long as possible. The second is correct for someone who only cares about limited years of usage and wants to minimize cost before dumping the vehicle (and its upcoming problems) onto someone else.

bc6152

If you do a search and look at all of the previous posts on this matter you'll have two weeks' reading to do. Opinions from users, experts, technicians, engineers, and backyard mechanics...


You can start with this one... https://www.clublexus.com/forums/es-...60k-miles.html

tronimrich

45k miles sounds very early for a fluid flush, but flushing is necessary to aid in vehicle longevity. The first time it was done on my '09 ES was at 90k, and again at 150k. Old mechanics would say you need to get it changed every 60k. If you drive primarily city miles, it may be necessary at earlier intervals. The oil wears and browns, and letting old/browned oil flow through your trans can damage the system through poor heat dispersing and/or clog it up with debris. I would think getting it flushed before 100k is NECESSARY

Get your transmission flushed fluid through the low pressure flush and 100% fluid exchange. Costs $350 or so. It is worth it if you want to get your car to 200k+ miles.

Fight tooth and nail to get them to do the process. Most dealers do not want to because they fear flushing old ATFluid will ruin the trans because of the possibilitiy of dislodging debris that is holding the mechanical parts together, which is something that happens when you never change your fluid, allowing the old/browned fluid to clog up the intricate mechanical slotting. Flushing at this point is too late, as it is likely that the trans is operating BECAUSE of the clogged debris.

Zipit555

I have been following the "to change or not to change" the transmission issue for some time. I am one of those keep the car for a long time kind of people. I have a 2016 ES350 with only 17,500 miles on it. (I avg about 4K-5K miles a year on my car.....mostly short trips) So for oil changes, it's a every 1 yr or 10K miles. Is there a time stamp on transmission change/flushes or is it strictly mileage based? Since I plan on keep this car for 10+ yrs, I am curious about the timing for transmission changes. I will likely only have 40k-50k miles on my car at that time. If length of time is not an issue for transmission fluid and it's only mileage based.......still not an issue for me........otherwise it is.

Thanks!

bc6152

Lexus says that the tranny fluid is permanent and not to be flushed or changed. Not time or mileage based. Never requires changing or refilling...

tronimrich

They say the fluid is lifetime. As in, it will last as long as it can before overheating the trans after losing heat exchange properties present in fresh fluid, or clogging it up with debris and metal flakes from being too old; both scenarios have been seen to occur as early as 120k miles. People who drive 150k+ mileage Lexus' are NOT the same people who think like you, that it never requires changing or refilling. People who drive 150-250k mile Lexus' are the types of people who have changed the fluid.

So when your transmission blows up at 120-150k miles via overheating from unchanged, burnt fluid, or you start having metal flakes in the oil because its too thick, well, thats your lifetime

pdxABC

Great answer. Thanks so much!

pdxABC

Thank you!!!

bc6152

Well I've never owned a car with over 50k miles except my 1931 Ford which had about 200,000 miles and used 80W transmission oil so I won't worry... BTW there are 112 posts on this subject in the link I posted above. Good reading for those interested in actually hearing from experts...

Seattle SCone

I changed my SC430's ATF fluid myself at 223K mile via 6 exchange rounds. Last time by dealer was about 100K. After all that time, shifts had become slightly delayed in shifting and included a very brief hesitation between gears. After the change, the AT is back to being smooth shifting and progresses appropriately under acceleration. The old ATF was nasty smelling and the color of root beer. At 225K miles now and I'm clearly in the subgroup who wishes to prolong the life of the transmission. If it were a three year lease vehicle or under extended warranty, the priorities may be different.

A. Exchange too soon and you waste money.
B. Exchange before fluid becomes degraded enough to no longer protect transmission and let it operate normally --- prolong transmission life
C. Exchange (or even worse, power flush) after transmission is damaged and avoiding slipping only because debris in its ATF is letting worn parts grab -- too late and new fluid might stop transmission functionality.
D. Exchanget at any time with wrong fluid or wrong fill level --> dead transmission.

I'm following plan B and I think 60-70K is probably about right based on what I saw of my vehicle's ATF after 120K mile interval. I clearly waited too long with 120K miles since the dealer originally did it.

There is a risk of unmasking a bad transmission after too long an interval. I'm suspecting that's why my dealership never suggested another change. If they change ATF on a high mileage transmission and it soon thereafter fails, it's a hassle for them. On the other hand, If I drive it with old ATF and the transmission dies at >200K miles. Well, it's only natural and they would be happily charge for a new transmi$$ion.

tronimrich

I've digested all the info you can on transmissions in this forum. I bought my 5th gen ES used with 150k miles, so transmission health and flushing was a huge concern. I would NEVER have purchased a used car with 150k miles if the transmission had never been flushed a couple times.

OP please take my concerns with the faith that I have done plenty of my due diligence. Make sure to flush your trans before 90k and then again at 60k intervals. If a Lexus dealership has recommended you flush at 45k, its likely you do a lot of city driving. I would flush at 60k unless I do a lot of city driving. Either way, get your trans fluid checked at another dealership AND ASK TO BE PRESENT SO YOU CAN SEE THE COLOR OF THE FLUID.

This is a GREAT video about transmission fluid health from 2:45-3:15 speaking about what actually happens with your trans fluid over its lifespan. Now, while we can't check our newer Lexus' transmissions fluid as easy as we can with a dipstick, I would totally recommend that when you get it inspected by a dealer, you be present to ask what color it looks like. The guy who created this 10 million view youtube suggests "lifetime" fluid is first inspected at a maximum of 100k miles :