Cocal

I don't have the hesitation, but I too use premium gas as the engine was designed with that in mind, also use the sport mode as it is more responsive. I think that these adaptive transmissions are the culprit and what makes it worse are dealers unwilling to spend the time to reset them properly. Dealers should be held more accountable by the manufacturers, all dealers and all manufacturers.

Machine13

I'm legitimately curious. Have you read somewhere that RX 350's have adaptive transmissions? I've read other threads in this forum where people said that Lexus does not use adaptive transmissions and there is no such thing as resetting the transmission itself. Further, I cannot find anywhere on Lexus' website, brochures or in the owner's manual indicating they use adaptive transmissions.

There is, of course, the ability to reset the throttle/fuel mapping by unplugging the battery for long enough. But that has to do with adapting the fuel delivery not an adaptive transmission.

I'm wondering if people are mistaking resetting their throttle/fuel mapping with resetting their transmission?

I'd love to see any evidence Lexus uses "adaptive" transmissions. I'm not talking about Lexus' smart transmissions that use automatic "AI" in real-time to enhance shifting based on driver's real-time throttle usage, because resetting won't do anything to change that AI behavior. But actual adaptive transmissions that store data that can be reset.

Cocal

As said by others either on this thread or another and I believe on the owner's manual as well, it doesn't call it adaptive, but it says that the transmission learns your way of driving to me that spells adaptive as I can't think of anything else that it would adapt to. When it gets reset one has to start all over again and the transmission has to re-learn your way of driving. Perhaps it is during this period that the problem occurs or there may be low ATF and the dealer, due to the amount of time required, is not willing to check. The Ainsin transmission has an outstanding reputation on its own, mechanical problems are unlikely and very rare. Or it can be like the owner that was taking the lexus back to the dealer because of a shaking of the steering wheel which turned out to be the lane changing alert coming into play and the owner didn't even know what it was. The owner's manual is the best kept secret for many owners.

keneaise

Just as a point of clarification, the RX was not designed to use premium gas since 2011. They recommend regular gas with a minimum of 87 octane.
See https://lexus2.custhelp.com/app/answ...xus-vehicle%3F

Cocal

All tests are done on premium!!! What the manual gives you is a Warning not to go below 87 that's not a recommendation. Do you see anything saying not to go above a certain number of octanes?

keneaise

Cocal, I really think a major issue could be that if the ECU uses driving characteristics based on the first thousand miles, it would be looking at break-in driving. No fast starts etc. I drove much differently then. Regarding most people not reading the owner;s manual, I simply think it is intimidating. It is by far the largest manual I have ever had from them, BMW or Mercedes. Not saying it is right but many find it easier to post on here to get answers.

keneaise

Of course not. Can't believe you would ask such a question. I attached a link produced by Lexus just for information. It says: "recommended minimum octane rating for all 2000 through 2019 Lexus models". That means it should run satisfactory at that octane.
I dont care to argue about this. It says what it says.

Cocal

I agree Keneaise, with my lexus I got two tomes and they are intimidating, but I had to at least skim through (did this on the Nav-Entert one) the mechanical one I did read. The one on my Benz was not as bad. Technology has enabled us to be a bit more lackadaisical, but I'm an old guy of the old school and trust technology up to a point only.

Cocal

This from page 685 of my owner's manual: Select octane rating 87 (Research Octane Number 91) or higher. Use of unleaded gasoline with an octane rating lower than 87 may result in engine knocking. Persistent knocking can lead to engine damage

I see this as warning You OTOH sees it a recommendation I don't want to argue either

Machine13

I just re-searched the entire 2019 owner's manual, all 777 pages, and nowhere does it say anything like "transmission learns your way of driving." In fact, the two words "transmission" and "learn" do not coincide in the same sentence anywhere in the owner's manual.

I'd really appreciate it if you can you tell me what page it says this in your owner's manual, and which year owner's manual you see it in? Or maybe if you could possibly be mistaken?

I really think this is a technical mis-conception that is worth clearing up for people on this forum if at all possible. Because any mis-information can only cause confusion for others. Please can you provide solid evidence, not conjecture, such as pictures, links or page numbers that Lexus states their transmissions are adaptive transmissions or other similar wording?

Thank you for helping get to the bottom of this,

GSFRX350

It says "Select octane rating 87 (Research Octane Number 91) or higher.", surely that means you drive into service station and select 87. Obviously you can ALWAYS use a higher octane fuel, won't hurt it but as that states they say or recommend to use Regular 87 and nothing less.

GSFRX350

Lexus may feel that there's no need to advise you that it's an adaptive transmission, it's a technical side of the vehicle that most people aren't interested in. Like ABS, the manual doesn't tell you how it works it just does it's thing when required or AWD, the manual doesn't explain that the drive is transmitted to the front wheels and to the rear wheels as required and that it can be constantly changing.
I too am under the belief that it is an adaptive transmission, my own experience with the car driving like a dog initially and then having the ECU reset by the dealer which fixed (mostly) my problem. I didn't mention the resetting to them only about the way it drove, they said when I collected the after the service then reset the ECU.

Htony

Software driven many gear shift tranny's purpose is to improve MPG for sure. Being software controlled, it ought to be learning tranny. I moved from Lexus to Benz.
Manual does not explain the complexity how it's proven 7 speed tranny works but shows how to reset(putting it to relearn mode) the box. It is done from driver's seat
with specific steps which takes about ~10 minutes. One can repeat the procedure multiple times to get the best out of it.. Then it'll learn your driving style(habits). I know
2015 Acura MDX had issues which made me to dump it. Lexus RX has same issues. But Audi 8 speed and BMW X5 8 speed, Benz 7 speed ones don't show this problem.
IMO, Lexus needs to improve it's software.

Cocal

I was talking about the 2017 MY, but it should be applicable to all years as far as I know. I remember reading somewhere that it would learn the way you drive, I can't find it on a quick search and frankly I don't feel to go through the manual on a semantic quest. As far as I know all AT have been adaptive/learning for the last 15 or so years, it was supposed to be "Progress" but the so called primitive engineering of the cars of the 50s is still going strong albeit with ingenuity (Cuba) I wonder if our techno riddled conveyance will do the same

P.S. Look also ate HTONY post just before this one where he too says that it's a learning transmission

john341

This is just a suggestion. When it is safe, dry and the weather is good, try turning off the traction control(stability control) completely by holding the switch for three - five seconds(you will see two lights when the traction control is completely off). I have noticed that when doing this, our highlander and Camry feels much more flat in turns, responsive(steering feel is much more natural) and most importantly transmission behavior changes dramatically to being quick yet smooth in shifting (no hunting or hesitation). It also seems to make the car relearn ones driving behavior quickly. I urge some to try this and report back. Also after resetting the transmission, make sure to come to a complete stop before continuing, and don't feather the throttle too much when driving for the first 100 miles or so, this is what the tech told me after updating and resetting my Camry trans (it works).