Transmission Issue - Dealer Claims Nothing Can Be Done

[jpto]

I just ordered a scan tool as a DIY techstream alternative (Launch Creader Elite v2) that says it can reset transmission learning, which could be an alternative to the dealer if they refuse. I'll post an update once it arrives

 

[GX550_OT]

I just ordered a scan tool as a DIY techstream alternative (Launch Creader Elite v2) that says it can reset transmission learning, which could be an alternative to the dealer if they refuse. I'll post an update once it arrives

Before you spend the money on a scan tool, you may be able to reset by taking the negative terminal off of your battery for 10-15 mins. I haven’t tried but this may reset the transmission memory.

 

[jpto]

Before you spend the money on a scan tool, you may be able to reset by taking the negative terminal off of your battery for 10-15 mins. I haven’t tried but this may reset the transmission memory.

good point, though I'd recommend getting a good scan tool if you do anything outside of the dealer. They're pretty essential these days for DIY tasks on modern Toyota's/Lexus (brakes, transmission, battery changes etc)

 

[RPMSTL]

Please do a review of the Launch v2 when you get a chance.. I'm currently in the market for a new scan tool.

 

[pterpelu]

Hey everyone,

First off, other than this recent issue, I love everything about my GX550. No problems or complaints, outside of maybe wanting a larger stock gas tank.

Currently at 11k miles, at 9k my GX started lurching/clunking as I came to a slow stop between 1-2mph. This happens regardless of whether my foot is on the brake or not. I took it in to my dealership to diagnose, and they are claiming there isn’t an issue, that’s just a “quirk of the GX driveshaft”. I’ve seen on this forum similar issues that were solved by resetting the memory on transmission, but they said they can’t do that without a software update.

It feels like it’s getting worse, not better. Even if it’s not dangerous, it’s like the hiccups: happens so often I’m constantly aware of or expecting it and it’s extremely annoying. They basically said it’s fine and if it gets worse, take it in, but I’m frustrated that I spent 80,000 on a new car and I have to deal with something that so adversely affects the driving experience.

Any advice on what I should do? I have an appointment with a trusted mechanic for a second diagnosis, but it feels like they told me I just need to grin and bear it. Thanks so much!!

I had transmission issues with my previous car, a Subaru Ascent. I kept complaining to the dealer every time I got maintenance and they just said, "it's a characteristic of the vehicle / CVT and none of our testing shows any issues." At 60K miles I got an email from Subaru offering to buy it back under the lemon law for basically the full original price. So I took the offer and applied it to my GX. You might explore the lemon law in your state.

 

[Letmride]

Great thread. I took mine in for a service and described the clunkiness and they reset the transmission. So much smoother now!

 

[SamIam]

Got my OT+ last week (come from a heavy mod'd 460 prior). Almost hyper sensitive to all the "issues" the forum is listing...none so far. Gotta tell you, notwithstanding all that...what an amazing ride...it's freaking cool....an upgrade so needed by Lexus.

I do see a little of the lurch as i come to a halt....and also a little rock back and forth bucking from time to time....but i'm playing with changing ride type to Sport or Sport+to see if it resolves...thinking it's fighting itself to be a "luxury smooth ride" otherwise. Anyone have any luck with that route?

 

[Shatter]

I just ordered a scan tool as a DIY techstream alternative (Launch Creader Elite v2) that says it can reset transmission learning, which could be an alternative to the dealer if they refuse. I'll post an update once it arrives

Did the scan tool work for reseting the transmission memory?

 

[jpto]

I haven't used it to reset the transmission, not having the issue, but it's in the menus as an option

 

[wlfkfgkwlak]

I've already commented on two other threads, but in case you missed it, I'm copying and pasting my comment here again.

"03/30/2025 - I confirmed with my dealership that Lexus has released a new transmission program to address the downshift issue for 2024 models. If you own a 2024 model, you may want to check with your dealership about this update.

For the 2025 model, Lexus has not released a new program yet. According to the dealership, the codes for the 2024 and 2025 models are different."

 

[Toxicdog]

Have about 8k miles now, and I have noticed both of these issues. Definitely have intermittent what I would call hard downshifts, so I’ll try the tranny reset. Also, sluggish shifts first thing. I really try to let it warm up, and also drive it in sport mode and both seem to help. As one person said, just get on it a little more and that seems to help also. I’ve noticed that helps with most driving characteristics on the GX. Anyone solved the issue with the A/C button always defaulting to “off”?

If you have it in Auto mode, the A/C button wont light up. In the climate menus, there is an auto a/c option that should be checked on from the factory.

 

[Roman]

Waiting for more updates from you guys. I told my dealer twice to reset the transmission module twice after the couldn't replicate the hard shifting while fixing my hood flutter issue. They said that all they need to do is disconnect the battery for 30 min... Not sure if they actually did it but hope this transmission update will fix the 2024s...

 

[Clack]

Talked with the head of service today at Concord Lexus in CA. He told me the reset was a temporary fix and it would come back in 3-5k miles but that he believes an actual software update is coming. FWIW

 

[RickBullotta]

To some extent, it's a side effect of a 10 speed tranmission. My Ford had similar behavior. The gearing is so close that sometimes the software seeks between two gears and misbehaves.

 

[Shatter]

Talked with the head of service today at Concord Lexus in CA. He told me the reset was a temporary fix and it would come back in 3-5k miles but that he believes an actual software update is coming. FWIW

Please let us know if you hear anything, I'm not buying one until I hear this is sorted.

 

[jclaffee]

To some extent, it's a side effect of a 10 speed tranmission. My Ford had similar behavior. The gearing is so close that sometimes the software seeks between two gears and misbehaves.

I agree with this. I have no downshift issues, but the somwhat weird gear hunting on acceleration is irritating, and very similar to what our 10-speed Silverado does. I guess I could just put in manual mode and use the paddles, but I haven't really played with that yet.

 

[Toxicdog]

Just went on a 5 day trip away from home and when I went to start up the gx, the fans ramped up to 100% for a few seconds and calmed back down. The harsh downshift at stop has completely resolved for the past few days. Are we getting OTA updates?

 

[ksj]

FYI - You can get a short term license for TechStream and do it yourself (plus apply available updates).
techinfo.toyota.com

 

[WhiteShark78]

At the dealership now. Brought up the reset etc.... They're going to see if someone is willing to do it. They're a little hesitant bc they said Lexus is aware of the problem and a fix is coming. It won't be a recall and you won't be told the fix is available unless you keep bringing it to their attention

 

[Shatter]

It won't be a recall and you won't be told the fix is available unless you keep bringing it to their attention

Ok, thanks for coming forward with the info. With that said... I'm out, I refuse to purchase a defect, this truck is a cobbled up mess. Lexus is fielding a 75k dollar problem for you all to solve. Not happening,