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Toyota Highlander Transmission Problems

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  • I have the exact same problem. I have had my highlander for 3 days and just noticed it. Did you ever find out what the cause was and the fix?
  • OK, what is the deal. Just purchased an 09 Highlander Sport AWD and noticed the same issue as both of you. Noticeable shutter when the accelerating uphill and the car shifts into 5th. Then the shuttering starts. I did notice it when we bought the car but thought it was the road. After several test runs I am convinced there is an issue. The Toyota dealer of course said we have not heard of any issues.

    Have you come up with anything???
  • wwestwwest Posts: 10,706
    Since they made a significant design change in their transaxle design back late in the last century that resulting in several unforeseen problems (poor thought process), Toyota has been struggling to come up with a FINAL solution. One of the fixes they tried very early on resulted in localized overheating of the ATF.

    It appears that as a result they have been overly cautious about the issue of more closely controlling ATF line pressure, ALL aspects of line pressure. The goal seems to be constantly keeping the line pressure as low as seeming possibly in order to reduce the ATF heating due to pressurization to the n'th degree.

    So I find it not surprising that some of you are getting clutch "chatter", shuttering, once you reach roadspeeds that dictate the use of higher gears ratios. Higher gear ratios reduce the need for high line pressure so my guess would that Toyota, yet again, is cutting things just a tad too close.

    That makes it all the harder for me to understand just why the solution Ford took for solving the exact same problem in the Edge transaxle design was not acceptable to Toyota.
  • I have it with the transmission folks now. I will let you know what happens. Seems to have to do with the fluid pressure and they may have to replace a part. More later.
  • wwestwwest Posts: 10,706
    Be careful...

    They might replace one of the pressure controlling solenoids which may solve your problem until the engine/transaxle ECU completes the (re)learning process for the new solenoid and then begins to optimize FE again.

    The engine/transaxle controlling ECU must get a "mind-wipe", go back to the factory default, rolling off the production line, parametric mapping, any time a new component of this class is installed.

    It might be wise, worthwhile, to know which solenoid they replace that you can later do a mod, provide a biasing current, should the condition return.
  • What you are saying makes a lot of sense. When I addressed the issue with Toyota service mgr at the dealer I bought my Highlander from he said it may have to do with the learning curve of the computer for the transmission. It has like the adaptive learning control that adjust the transmission to your style of driving. He said to put on at least a 600 to 1000 miles on the vehicle before being concerned. Might be BS but I will wait a while and see if it corrects itself. This problem started from day 1 of the purchase so we will see.
  • wwestwwest Posts: 10,706
    The electronic control system of most modern day automatic transmissions make use of several 12 volt electric solenoids. Most of these operate in simple servo "bang-bang" mode, on/off, plunger either fully relaxed (spring return) of fully deployed.

    But there are 1 or 2 functions that require "linear" displacement of the solenoid actuator plunger, line pressure control for instance. Eons ago it was considered that a simple electric solenoid could not be used in this manner. Then along came the idea, ability, to modulate the plunger position "linearly" via the use of PWM, Pulse Width Modulation, voltage duty cycle control of how far the actuator was to be deployed.

    The next problem was, what was to be used as feedback to the controlling device to denote the actuators control position...?? A new off-the-shelf solenoid could be roughly "calibrated" insofar as voltage applied vs actuator movement/position and while that might be close enough for the factory default control mapping parameters it was not satisfactory for the fine position tuning control required once installed within the vehicle.

    The answer was...The function being controlled. Clutch slip within the transaxle...?? Increase the line pressure via a slight increase in PWM voltage. You didn't need to calibrate the solenoid to exacting actuator position, that could be done "on-the-fly" as the vehicle is driven.

    I believe the first use of this technique for automobile engine control was to control the idle air bypass valve. Two feedback sensors are used to do this, the upstream oxygen sensor an an engine RPM, timing sensor. The solenoid must be adjusted to the point of allowing just the right amount of air through the bypass port that the idle air/fuel mixture is correct in accordance with the upstream oxygen sensor(s) and the RPM remains at a steady 800RPM.

    Disconnect the battery and the IAV control will default to the factory parametric PWM settings, but after a fairly brief period of time the ECU will have learned, pretty much exactly, what level of voltage is required to hold the solenoid in the correct "linear" position to satisfy the feedback parameters. Now it will go to that "setting" each and every time you start the engine.

    Plug up the bypass port slightly with debris, oil wicked into the intake path from a K&N followed by dirt, the ECU will simply re-learn, again and again, over an over again, the level of PWM voltage to be used to "meter" the proper airflow.

    Plug up the bypass port too much and the solenoid will not have enough range, you get a CEL. Clean the bypass port and over a period of time the ECU will have learned the new parameters. Disconnect the battery and that period of time will shorten.
  • wwestwwest Posts: 10,706
    "..adjust the transmission to your style of driving..."

    What your service manager doesn't understand, "get", is that there are two categories of ECU learning/relearning. Yes, the engine/transaxle ECU will "watch" how fast you "normally" depress the gas pedal AND how fast you "normally" release it. The time it takes you to move your foot from the gas pedal to the brake is even important insofar as adapting to a specific driver's driving style.

    But parameters of/in that category MUST be erased for each an every stop/start engine cycle.

    But there are MANY other engine/transaxle control parameters that must be learned and/or continually relearned as you drive. Let's say the knock/ping sensor "sounds off" during acceleration (excluding engine lugging with a stick shift and/or ignition timing too early). The ECU must quickly adjust, enrich, the A/F mixture via EFI to abate the knock/ping. But now the engine will be operating below the factory design "standard" and the ECU will periodically run A/F mixture leaning, optimization trials, in case the engine is now being "fed" with the proper, premium, fuel.
  • Any news on your Highlander yet from your transmission folks? Just wondering if they found the problem so I can let my dealer know what to look for.

    Thanks
  • Update: Transmission guys are puzzled. The good news is that they're honest and are very certain it is NOT transmission issue. They have replaced the mass air flow thingy (it was bad) because they were getting a diagostic indication that it was a problem. Result: No fix. They also thought it may be the crankshaft sensor and replaced that. Result: No fix (they are crediting me back for that part).

    Again, just to be clear, I had my engine replaced and the car immediately starting bucking/jerking in the lower gears (like, within 5 miles of leaving the service center). This is appearing to be an issue related to the computer/electronics as a result of how the replacement engine is "talking" to the car/transmission.

    Curious thing is that one would think that Toyota or the shop that replaced the engine would have experienced this before. That is: Engine replaced = car doesn't shift properly. But they are stumped.

    They still have my car and are now talking to some other "expert." It has become a bit of a lab experiment, I think. I will tell you this...I have owned 10 cars in my lifetime and will NEVER buy another Toyota. If I had taken the time to read all the negative things on the Internet about how poor their customer service is, I wouldn't have bought the Highlander either. I think Consumer Reports must be getting bought off by Toyota.
  • wwestwwest Posts: 10,706
    ".. NEVER buy another Toyota.."

    That may mean, in effect, "jumping from the frying pan into the fire."

    Is there, today, a "better" marque overall...??
  • Any change in your shutter issue??? I have an 09 Highlander Sport AWD with 350 miles on it shutterd from day one when the transmission shifts into 5th gear prematurely. I think it has to do with the rpms not being high enough to support 5th gear thus putting stress on the clutch plates. Kinda like a motorcycle that is lunging when the gear is to tall for the speed and rpms. Not sure why mine keeps shifting into 5th when it is obvious it should stay in 4th. When it does this the rpms are at 1000 to 1200. Way to low to support proper engine/transmission speed thus the shuttering starts until I hit the gas to cause a downshift back to 4th gear.

    Back to the dealer I guess. Have you had any luck getting yours fixed????
  • tavutavu Posts: 2
    My owners manual does not cover the auto transmission for some reason. It states the type of trans. fluid to use but does not state the correct way to check the fluid level. Can someone help me? Is there a "supplement" manual out there that someone has heard of ? Thanx...............................
  • Sorry to reply so late. Took my 2003 HL to Toyota and the net-net is that they needed to reset and recalibrate the ECU (computer). The transmission, etc. checked out okay. Bottom line, again, with mine was the engine was replaced, and only Toyota has the laptop/diagnostics to recalibrate the car to zero so the transmission is resynched. I think my issue was different that some of the others on the thread, even though the systems are the same. Good luck with yours!
  • mdhuttonmdhutton Posts: 195
    Most trans fluid is checked with the engine off, but the fluid hot. Not sure if your vehicle is different, though.
  • Just joined the group - thought I'd pose a transmission related question. I just bought a new '09 highlander sport V6 4WD which now has about 300 miles on the clock. I am experiencing small vibrations through the chassis under certain circumstance. It's taken a week to figure out how to recreate the problem, but it seems to occur then the transmission has shifted up to a high gear (not necessarily top gear) and you drive on a very light throttle (almost lifted off) with about 1500rpm on the tacho. It's as if the car is hesitating not quite able to decide whether to kick down or perhaps there's not enough torque to force it at these revs with such a light throttle. Give the throttle a bit more of a kick and the car shifts down easily and the vibrations disappear. It's taken a while to pin it down but I can repeat it almost on demand and it's seriously affecting my enjoyment of what is otherwise a beautiful, smooth and refined car (perhaps that's the problem - it's so close to perfect, you notice the smallest imperfections - I had an Explorer V8 before - enough said!!). Anyone else experienced this. I'm prepared (hoping) to believe that this is because it's new and not run in yet and thus everything is a bit tight and may settle down, but I wanted to hear from anyone else who has experienced this and if they cured it (how?) or if it went away with a few more miles on the clock.

    Will ring the dealer Monday and ask their opinion but if there's others out there with this issue, it'll add weight to my case
  • Well, as you can see by my previous post I have the same problem with the same vehicle. I am now wondering if it is isolated to the Sport V6 AWD. We have the same exact model and both are experience the same exact problem. I also have to give it a little more throttle to clear up the issue. So now I just drive it a little more aggressively. Not a cure but a temp. fix. My dealer said bla bla bla. Meaning they said they have never heard of this before problem before. I am like you and now am NOT enjoying our new car as I first did. We have 450 miles on ours with no change. Might have to live with it. I thought it might have to do with the big 19 inch tires and stiffer suspension set up on the Sport. However, I am at a loss. Maybe should have gone with the ugly new Honda Pilot.

    Did you dealer give you any ideas???
  • vttacovttaco Posts: 6
    Howdy: i too recently purchased a 2009 Highlander; only 500 miles. I am experiencing the same shuttering under same conditions.
    Its at the dealer today; waiting to hear back.
    the service guy causually referred to this as 'normal' but back pedaled when I expressed my concern and stated this was unacceptable.
  • Please keep me informed as to what your dealer finds out/tells you. If they are able to isolate the issue please let us know what it is. We can then pass along this information to our dealers for resolution. Either way, let us know what your dealer tells you.

    Now there is three of us in the past few days on this message board with the same
    problem. Nice Toyota.
  • vttacovttaco Posts: 6
    Howdy Again:
    I just got a call from my Highlander Service Dept Rep:
    According to him "They have heard of this before". And want to keep my car for a day to full look at this and 'nail it'" They are being very responsive, and will be providing me a loaner vehicle while they investigate.

    More after they report back tomorrow...
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