Tranny keeps forgetting to step down gears

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WTITW said:
That sounds very similar to the behavior Im seeing. I’ll take this to the transmission shop.

thanks buddy. You’re the encyclopedia of GX.
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I usually just call him, "Wiki Acrad".
 
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Acrad said:
Wonder if somehow related to this ECM calibration?

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Looks like there is supposed to be a sticker that shows either the old calibration numbers or the new. Mine doesn’t have a sticker at.

D349B4BE-5F4C-46C5-82FD-2CBA6F3EAEB5.webp
 
I believe that sticker is applied if the TSB had been performed. This would show up in your Lexus service record as this would likely have been a dealer only thing in the day.
 
Acrad said:
I believe that sticker is applied if the TSB had been performed. This would show up in your Lexus service record as this would likely have been a dealer only thing in the day.
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No record in drivers history and the first owner had extensive Lexus visits. Can I somehow get to these settings in Techstream to confirm it’s not been performed? I wouldn’t want to change it myslef, since I’m an a55 clown of a mechanic…
 
It looks like Techstream is used by dealer to update ECM. Of course... this isn't some file you can download... you could with a TIS subscription but I'd be highly paranoid about home flashing with our TS setups.

Take a look at this TSB on TS flashing. It does appear you could view the calibration number(s) after a health check as per page 8.

 
Acrad said:
It looks like Techstream is used by dealer to update ECM. Of course... this isn't some file you can download... you could with a TIS subscription but I'd be highly paranoid about home flashing with our TS setups.

Take a look at this TSB on TS flashing. It does appear you could view the calibration number(s) after a health check as per page 8.

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Looks a little iffy for my skill level. I think I’ll just take the sheet and the matching symptoms to the trans shop and see if they can check it, if they can’t I’ll take it to lex and have them either confirm it was done or recalibrate. The TSB says it’s only .6hrs so even at lexus prices, that’s probably only around $500 : ) God it would be great if it were that simple.
 
If I get some time tomorrow I will see if that calibration number shows up just in the data list for AT with TS.
 
You can pull the calibration number fairly easily with Techstream.

Select Health Check
IMG_3454.webp


Select Just Powertrain
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Next and then you will see

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Just hit continue when you see this screen

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Calibration info will show up when finished. No idea if these Calibration IDs are mapped to a year or not. I don't have a TIS subscription.

IMG_3459.webp
 
I noticed there is a subsequent TSB that doesn't seem to be available at NHTSA. Perhaps someone can find it on TIS site?

www.nhtsa.gov

Vehicle Detail Search - 2010 LEXUS GX460 4 DR AWD | NHTSA

www.nhtsa.gov www.nhtsa.gov

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This again has a newer calibration number and seems to affect some early 2011 models as well.

SB-0146-10

www.autoserviceprofessional.com

Lexus non-linear acceleration

Some 2010-2011 Lexus GX 460 vehicles may exhibit non-linear acceleration from a stop under certain conditions of low engine rpm with high engine load. The ECM logic has been revised...
www.autoserviceprofessional.com www.autoserviceprofessional.com

Some 2010-2011 Lexus GX 460 vehicles may exhibit non-linear acceleration from a stop under certain conditions of low engine rpm with high engine load. The ECM logic has been revised to address this condition.

PREVIOUS CALIBRATION ID: 360E1000 / 360K0000

NEW CALIBRATION ID: 360K0100



TARGET ECM: SUB

PREVIOUS CALIBRATION ID: 56052000

NEW CALIBRATION ID: 56040000
 
I saw a single post about this TSB from 2011 here on post #45 at CL

New GX 460 - ClubLexus - Lexus Forum Discussion

GX - 2nd Gen (2010-2023) - New GX 460 - After reading here for a couple of weeks I took the plunge and bought a GX today. It is coming from another dealer so I don't get it until Tuesday and I can hardly wait. It is a premium model in Claret Mica. Thanks for all the info in the forum it was a...
www.clublexus.com

Screen Shot 2021-08-09 at 10.59.24 AM.webp
 
Acrad said:
It looks like Techstream is used by dealer to update ECM. Of course... this isn't some file you can download... you could with a TIS subscription but I'd be highly paranoid about home flashing with our TS setups.

Take a look at this TSB on TS flashing. It does appear you could view the calibration number(s) after a health check as per page 8.

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Lexus said sounds plausible after checking out the tsb and my Lex drivers history. Got an appointment for Wednesday. I’ll update after. Thanks again, you’re an invaluable resource here.
 
Lexus did the software update today and confirmed it had not been done before. I floored it from a slow roll a few times in the Lex driveway (service wasn’t very good) to check it and and it downshifted right into first every time. Ill check it again in the am when it’s cold.
 
WTITW said:
Lexus did the software update today and confirmed it had not been done before. I floored it from a slow roll a few times in the Lex driveway (service wasn’t very good) to check it and and it downshifted right into first every time. Ill check it again in the am when it’s cold.
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Were you ever able to do your little weekend trip with the family last weekend? Or decided not to because of the tranny.
 
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