2018 Toyota Highlander Limited we just bought from Corwin Toyota in Colorado Springs. The car is currently there getting fixed and serviced for lurching forward issues on gas pedal is pressed. it also happens on slowing then accelerating. clearly the transmission is messed up.
Within days of buying the car the transmission (the 8-speed everyone talks about) lurches forward with a delay on giving gas and slowing down. it lurches then goes. its getting worse too. Car has just over 60k miles. dealer tech claims they want to drain the transmission fluid saying “we recommend this at 100K miles” when we asked why, knowing this is bad because you dont drain trans fluid routinely at a service interval under 100K on a newer car with just over 50K miles. instead of being upfront, we had to find out ourselves that this engines from 2017 to 2020 have a super flawed 8 speed engine that does exactly what ours is doing. they are right now trying to blame it on several other stupid things we know its not, like AC, which we haven’t even used once yet buying in the winter and still its not summer, the brakes, which are fine, ABS, which is fine and engine sensors which ALL are fine. they are trying like hell to avoid the discussion. So were going to start a warranty claim on the transmission and get the whole thing replaced or get a recall effort going first. this is totally unacceptable and were going to begin a relentless complaint to warranty dept. Anyone have any advice let me know.
If the engine, brakes etc etc has been cleared of the lurching forward issue then next is checking the transaxle… The SLT solenoids operation is based on signals from the TPS (throttle position sensor) and the VSS (vehicle speed sensor)…
You have the UA80E/F transaxle (E = FWD and F = 4WD or AWD) from 2017-2022 behind the 2.5L and 3.5L engines…
1st thing that has to be known is what codes are stored if any, engine and transaxle/transmission… Also one of the 1st things that has to be done is to make sure the ATF fluid is full and not low, they are not always full when they leave the factory, or even after leaving the Toyota Dealer new car prep… It has to be done per the manufactures recommended process…
It is best to do a drain and fill service on these transaxles every 60K miles, no matter what the dealer says…
The UA80E has two pressure check locations, one for forward ranges and one for the reverse. Forward pressure (with the engine idling) should be 73 to 102 PSI. The pressure should be 189 to 232 PSI during a stall test. In reverse (and the engine idling), you should have 73 to 102 PSI. The pressure should be 247 to 305 PSI during a stall test.
After checking for codes and both the forward and reverse pressures, the tech can evaluate what the conditions are. If the pressure reads high in all positions, then possible causes can be the SLT (shift line pressure) solenoid (controls the main line pressure) is defective and or the pressure regulator valve is sticking.
A feature of the UA80E/F trans is the torque converter will apply in any gear (including first) based on the driving conditions. The SLU (solenoid lock up - controls the TCC (torque converter clutch)) solenoid and the SL solenoid (shift lock–switches the lock up relay valve) the SLU and SL solenoids are either on or off…
If the forward pressure only reads low in the drive position, you could have a fluid leak in the number one clutch, and or the number 2 brake, and if it also has the main line pressure valve sticking then it might be possible that forward gear(s) is flaring making it feel like a surge… but I really doubt it…
A sticking or high pressure main line pressure valve as well as a sticking SLU/SL valve(s) could be applying or trying to apply the TCC to early causing the lurching issues, but it could be a number of issues, Toyota might already have a fix for it, but they also might just warranty the trans and TCM out or something…
Me? I might, depending on codes and pressure readings, replace the valve body assembly and or the TCM, or probably just have the TCM flashed with the latest software update 1st… A lot of different transmissions issues have been solved with TCM updates…
Sorry you are having this issue, Toyota make a great vehicle, but nobody is perfect…
Please keep us informed on what they find…
You’re right that the the owner’s manual probably recommends more than 50K b/t trans fluid refreshenings, but some folks here recommend as little as 30k . The dealership shop’s recommendation to do it now seems reasonable, given the symptoms and as yet no clear cause found. The above advice seems sound too, esp the trans fluid pressure checks, provided the transmission is the actual problem. I’m not convinced of that theory so far. Could be the trans, but more proof is need in my humble knucklehead diy’er opinion, no 2018 Highlander experience.
I’ve had similar symptoms on my manual trans car caused by the idle air control, and there are other engine-related potential causes as well (especially the throttle position sensors and actuators). The only time I’ve had an auto-trans problem (on my other vehicle) , the symptom was when shifting from N to D when cold, it wouldn’t engage, engine rpm increased but vehicle remained still, like it was still in N. The solution for that problem was a complete trans rebuild, which fixed the problem right away.
Your vehicle is embedded-computer-controlled, multiple computers, and this makes it complex. Suggest to just let the dealership shop techs go through the manufacturer’s suggested steps, rather than try to diagnose the problem yourself.
Try to keep all your conversations with the shop in writing, w/a time and date stamp. If you have a verbal conversation, write it up and give the dealership a copy, ask them to clarify (in writing) if they disagree with your document. If after doing all this you still think they are completely on the wrong path, get a 2nd opinion from a different mechanic. Frustrating I know, but this sort of problem is what comes with complexity. And new car buyers like all the functionality & convenience that results from the complexity. Best of luck.
If you want to do something yourself, suggest to visit your local public library and ask them what sort of resources they have that will allow you to research the known issues with this vehicle. Ask about service manuals, service-data-bases (like AllData), etc. Tell the library staff idealy you’d like to find a list of the published tsb (technical service bulletins), recalls, customer service programs.
Thank you for all this info. we are saving all texts and emails as you said.
So today we confirmed INSANE info. Not only is there a law suit on Toyota over this 2017-2020 8speed transmission for failing in all highlanders and siennas from 2017 to 2020, our tech at Toyota just told us if the transmission doesn’t improve they are going to start a extended warranty claim to replace the transmission. the car is a 2018! one previous owner. in perfect shape. motor and trans are brand new!
check this article out on the current class action lawsuit Toyota has going on these transmissions
Apparently Toyota is getting some of these 8speeds and rebuilding them to try to correct the issue. So if you have your transmission replaced it will be a Toyota rebuild of the SAME thing.
There isn’t much correction they can do though. early on your tech may say things like the fuel filter or throttle body or AC or ABS or brakes, etc… this is totally them killing time. They are ALL AWARE of this and they never told us when we bought this car. We are more upset at that than the cars trans going out but were here so we gotta make the best of it.
the REAL solution is this. We are going to fix whatever is wrong with this car and trade it in (we just paid $32,000 for it). Were going to buy a 2021 or 2022 with the other transmission. Otherwise you are always going to have trans problems. Rebuilding the engine cannot take away inherit problems. The problem is the 8 speed gearing. It is FAR too close and does not work well with V6 engine and it also has other tweaks done to it to make things worse such as additional electronics and sensors placed in and around the 8speed trans causing all kids of issues with OTHER sensors, O2s, fuel pump, etc… its a mess.
If you opt to get a rebuild (and your tech may tell you its a new trans but its not) its a Toyota certified rebuild which is new on paper but not when you look at it. The rebuild may have better seals or changed gearing but that leaves other issues on the spectrum later on.
Our car is currently in Toyota and if it ever goes back they are opting for replacement.
They did a trans oil change, they relearned the computer and told my father it will take a bit for the transmission to get used to his driving habits which is exaggerated really - as were experiencing a FLAWED trans, not a new car drive learn period.
The best thing is to trade in your car while you can. Were expecting to lose a lot of money in this process but what can you do? Our hope is since we JUST bought it were going to demand and squeeze as much trade in value as we can or were reporting all this on reviews, BBB and werre jumping on the class action lawsuit.
Below is the Customer Support Program document for certain 2017 - 2018 Toyota Highlander transmissions. Warranty coverage is for ten years from date of first use for vehicles that were built during specific build dates. The bulletin describes the assemble defect that results in transmission failure.
Does your state have a period during which time you can return a used vehicle? If so…
thank you! after the long rabbit hole of TSBs, the class action lawsuit over this UA80 transmission and the Toyota misguided ideas, this was the service program we were hoping for.
Our tech has already acknowledged they may have to replace our transmission, likely with a rebuilt certified trans.
Toyota just tried to skate around this program and blame it on several symptoms that are a direct cause of the transmission. now they’re indirectly addressing it. too much legal liability.
yes our period was 30 days to return it. we’re past that by a month. in any case we’re covered by the extended expensive warranty we got on the full power train. even if we didn’t have the trans covered we’d fall under this 10 year extension for our model and production so folks who didn’t get trans coverage look into this UA80 transmission service program.
it’s their answer in 2019/2020 to this ongoing problem of lurching stuttering issues of your direct drive 8speed UA80 transmission.
at least this is what a Toyota tech told us. If you don’t have a warranty they will file an extended warranty claim for you to swap the transmission. however be aware they won’t admit the transmission is flawed. they’ll drain the trans fluid and try all these other things including reprogramming your computer and tell you the car has to relearn your driving habits. this is exaggerated because this doesn’t cause what the transmissions symptoms are. just know they know full well what’s going on and will eventually replace it if the transmission issue persists but only after eliminating other “fixes” that may not work so you’ll be going back again if it continues. We are about to pick up our 2018 Highlander limited today after they did this stuff while telling us if it persists “we will start an extended warranty claim and replace the transmission”.
Did you verify the vehicle’s manufacture date on the label on the driver’s door pillar? The customer support program only applies to vehicle manufactured during a certain time period.
The technician must rule out any other causes of the symptoms of your concerns. Toyota will require evidence of transmission failure before approving replacement of the transmission. The service department is the “middleman” in this transaction.
Nevada_545 you were right, the tech just told us that the program isnt showing up for our production date although it is under the same year and ONE month away from production. whoever made those production dates were VERY biased in deciding those dates. which is really frustrating that the SAME thing described in this program is happening to the SAME engine thats now discontinued AND in several lawsuits currently. All same symptoms lurching, stuttering, loss of power, etc, in a otherwise new transmission. they do have service programs for both the high and low fuels pump leaking issues which well address later. funny how the fuel pump exploding and leaking was ALSO under this related tsb that lead to this UA80 transmission replacement program. lots of legal road blocks of a wide spread issue that unfairly cuts others off. this is what a judge likely awarded the most common complainants at the time in 2019.
the good news. we have the power train warranty that DOES cover it from another angle. THANK GOD. The tech said - otherwise wed be paying out of pocket.