Greetings!

My 2020 ES350 UL has that dreaded jerky transmission. It is most pronounced at lower speeds. It vibrates the car at low speeds and shifts roughly. It is also heavily pronounced between 30-35 mph. Nevertheless, I have read a lot of threads about this but did not find anything conclusive. Can anyone confirm if the dealership can do a transmission software upgrade or some other fix? I will note that I have a scan tool that can force the relearn procedure. I did that and it helped DRAMATICALLY; however, that disappeared after the month mark. I'm curious if there is a permanent fix.

Thanks!

 

The lexguide.net Lexus ES (XZ10) Service Manual's Ua80e (automatic Transmission / Transaxle) - Initialization procedures in the "PERFORM ROAD TEST TO ALLOW ECM TO LEARN" section have a "Road Text Pattern" graph/procedure (scroll down about half of the webpage) to repeat "until the shift shock and engine speed overrun (engine speed flare when shifting) reach an acceptable level." I don't have any personal experience with that procedure, but that's the Lexus "official" procedure for retraining the transaxle's ECM after the ECM memory has been reset.

You might try resetting the ECM memory again; perform the road test procedure as specified; and then see if that results in smooth shifting for the long term.

Also, for a 2020 ES350, you might want to look at Technical Service Bulletin (TSB) L-TT-0288-20, Vehicle Drivability Complaint Questionnaire on "… vehicle surge/hesitation condition (inconsistent acceleration) …". While that TSB won't necessarily fix your problem, at a minimum it can give you a "Lexus is aware of…" documented foundation to use in any discussions you may want to have with your Lexus service department.

 

What is present mileage on the car?
Are you the original owner, if not at what mileage did you purchase?
How long has this tranny shifting and jerky/vibration operation been a problem?
Has the transmission ever had any repair work done which would involve a fluid service, if so if you know who did the work?
Has the tranny fluid level been checked?
Are there the same size tires on the front axel and pressured the same?

 

Very good information; thank you @grp52 !

 

Yes.

Thank you for your response and please see the responses above.

 

FYI, most likely the transmission fluid level wasn't checked by the mechanic that did the Pre-Purchase Inspection (PPI). Like most, if not all, lifetime-transmission-fluid transmissions/transaxles like the ES350's UA80E transaxle, there isn't a transmission fluid level dipstick that allows for simple, easy transmission fluid level checking.

Although there are procedures to check the automatic transmission fluid level in the UA80E transaxle, the time and effort required to accomplish the fluid level check procedures are such that even the best Lexus expert mechanics would forego performing the transmission fluid level check unless during the PPI the mechanic found something that would raise a suspicion that the transmission fluid level may not be correct.

To give you an idea of what's involved in checking the ES350's UA80E transaxle's automatic transmission fluid level, the lexguide.net Lexus ES (XZ10) Service Manual has two types of procedures for checking the level. One, within a narrow band of fluid temperature (35 to 45°C (95 to 113°F)) that is less elaborate, is Ua80e (automatic Transmission / Transaxle) - Adjustment. The other, at a higher operating temperature (85 to 90°C (185 to 194°F)) that is more elaborate, is Ua80e (automatic Transmission - High Temperature Adjustment.

That said, over the years in the multiple threads discussing jerky transmission shifting, I don't recall incorrect automatic transmission fluid level being raised or discussed as a possible cause of jerky shifting. Implicitly or explicitly, everyone just assumed/assumes the factory fill-resulting fluid level was/is correct, and improper automatic transmission fluid level wasn't ever entertained as a cause of jerky shifting.

 

Thanks for the detail info.
I meant by checking the tranny level since no dipstick in the 7th gen ES350 sealed unit: raise level on lift, get the tranny fluid up to the desired temp range, pull the drain plug and see what volume comes out the internal tranny level standpipe. If a small drip/trickle that is ok, if no fluid that would at least be a need to add some fluid even as you note fluid level has not been related to the jerky tranny issue.