Toyota Avalon 2005+ Transmission Questions

captain2 · June 2006

scoti1 - would suggest to you, as I posted earlier, that 90% of us Av owners out there do not find it terribly bothersome and that, of those that do, the inability of the system to adapt to an all-on/all-off driving style is likely the culprit. The Avalon simply does not respond correctly to sudden throttle changes from lower speeds, make it a firm (but gradual) application of throttle and the problem 'disappears'. Wwest is correct, there are certainly livable DBW systems out there and there are also many that, in one form or another, are even worse. But, either way, it would make no sense that one Avalon would be different from another - until it has had a chance to 'learn' something that it can't cope with.
From my point of view, the jury is certainly still out on all this electronic control crappola being put into all cars these days. It will get worse before it gets better and is certainly something we all will have to live with.

oilcan2 · June 2006

Don't want to sound silly but if there is some time/mileage
point where the trans stops learning and doesn't learn any
more,than maybe we need to get trainers for these transmissions,have someone whose trans is perfect train
your car for you.I wonder if we had all the posters with
problem transmissions switch there cars with the non-problem ones and let those drivers train their cars what
would actually occur.

wwest · June 2006

There could, of course, be a quite reasonable explanation for engine response to the accelerator pedal while in park or neutral. Were I writing the control firmware in this case I might delay the onset so as to be sure of the driver's intent.

Application of pressure to the acceleration pedal while in park or neutral would in most cases be an anomaly, Ooops, bumped the pedal and only sustained application "should" be responded too.

And no, I never heard that Nova story/rumor but there is the one about a clone of Ken Olsen's 16-bit off-spring rescuing the pioneer 10 program as the probe exited the solar system.

scoti1 · June 2006

oilcan2,

If you follow wwest's posts on this and other boards, you will see that the hesitation does not appear to be a transmission learning issue. Wwest has looked into this and found that the learning resets itself everytime you start the car and makes judgements on your driving style within the first few minutes of driving. I am completely non-technically trained so I am sure wwest can explain this better. but if this weren't the case, how could you ever have multiple drivers on one car, especially rental cars?

oilcan2 · June 2006

Guess I'm trying to establish what the difference is from
one avalon fron another,assuming no mechanical problem,it
would be interesting to get a driver who has a so called
perfect av trans(even if it's in his mind)to drive a problem one and see if he has any luck with the trans.

havalongavalon · June 2006

Hi oilcan2,

This difference may be among drivers; not cars. Numerous Avalon drivers who had "hesitation" problems were able to improve their car's response by changing the position of the foot on the gas pedal.

Changing their foot position seems to have worked also for readers who drive other car brand with similar problems. See

#11794 How do YOU step on the gas pedal? Initial Poll Results

and many following posts.

havalongavalon

scoti1 · June 2006

Yes, that would be a good experiment and would help glean information on whether it is completely a driving-style issue or one that is mechanical or software related in a certain number of vehicles. I know some drivers with the problem have been able to drive similar models and not experience the same problem, so my opionion is that, while the problem may be exacerbated by driving style, it is not the root of the problem.

camadden · June 2006

So, I guess that I'm in good company ! Just wish that I had done more research before I bought. I'll know better next time. Thanks for the info.

neil5 · June 2006

today in for 5k service. I asked them to check out my tranny, even though I have not had bad performance occasional slippage on turns. They are checking for service up dates, softwareupdates and roadtesting the vehicle and doing computer check...I live next door to head manager at dealership so I will let you know what comes up. Happy with the Avalon..far better than 07 camry I have been driving today...not as large or refined...I'll keep the Av...

gohawaiian · June 2006

My month-old Avalon occasionally (not always) does something that feels odd to me. I'm wondering if it's normal & something that other owners have also experienced: when I take my foot off the gas pedal, it sometimes feels as if the car has downshifted into a lower gear, because there is a slight feeling of drag or resistance slowing the car down a little (rather than just continuing to coast along as if the car were in neutral.) Is this slight engine-braking (if that's what it is) a cause for concern? Has anyone else noticed this?

havalongavalon · June 2006

Yes, this can happen, for example if you are driving down a hill, and is no reason for concern. When you take the foot off the gas this means that you want to continue at same speed or slower. If you are going down a hill, the car could gain a lot of speed even if you don't give it any gas. So when you take your foot off the gas pedal and your Avalon responds by downshifting, this helps to resist the gravitational acceleration and keeps the speed under control.

If you prefer to let the car gain speed down a hill, and don't like this automatic downshift feature, you can usually override it by shifting manually into "S" and nudge it into 5th gear. If traveling at a slow speed, nudge it into the next gear up from the gear that is engaged.

havalongavalon

gohawaiian · June 2006

Thanks, Havalong. That's a real surprise. I have never felt a car doing that before. When did cars begin downshifting like that by themselves? Is this phenomenon now commmon on most new cars, or just recent Toyotas? My car downshifts by itself not only going downhill, but frequently on level roads, where the downshift seems clearly inappropriate. On level pavement, after 5 seconds or so, the car will shift back to the proper "drive" gear, as though the computer has belatedly figured out that the downshift was a mistake. I find it quite disconcerting especially if there's no downhill incline and therefore no reason for it to downshift. (I wonder if this may be a case of too much electronics for the car's own good, causing it to go a little haywire occasionally.)

havalongavalon · June 2006

Hmmm. gohawaiian, you may be experiencing the "sometimes indecisive transmission" behavior. Watching your RPM may tell more. My car selects the highest possible gear but downshifts when the RPM drop below 1400 or so. Then if the speed picks up a bit or the slope changes, it may downshift again. It normally doesn't shift up and down very frequently unless the terrain calls for it.

Is this happening to you while in "D"? Have you tried shifting to "S" and 5? This seems to help reduce indecisive shifting.

havalong

gohawaiian · June 2006

Thanks havalong. As I'm not familiar with a 5 speed automatic, maybe it is just doing exactly what it is supposed to do. The sensation of resistance or drag that I sometimes feel on level pavement occurs when I take my foot off the gas at speeds under 40 mph. I watched the RPM indicator as you suggested and did not see it move up at those times when I feel the drag or resistance, so the car is probably NOT downshifting. As I mentioned, though, after several seconds like that, the slight feeling of resistance disappears and at that moment, I see the RPM needle fall from about 1400 to about 1100. I wonder if maybe the car, while at speeds under 40 mph, has been in 4th, and as it slows down & coasts when I take my foot off the pedal, could it shortly thereafter be upshifting into 5th? Would that be the expected behavior of the transmission as the car coasts on a level road and its speed falls? If so, that would explain the feeling of drag that shortly afterwards disappears when the RPM needle drops. If that's all it is, then I guess the only question I have is whether all Avalons do that & it is completely normal? Thanks!

neil5 · June 2006

Well some good news and top of the heap:
http://www.automobilemag.com/am/2006/toyota/avalon/safety.html\

The safest Vehicle out there for side impact.

camadden · June 2006

Thanks. I would apprecate any info that you can get as i am in the process of formally filing my dispute.

bobwiley · June 2006

The infamous auto trans problem jumped up and bit me. I have an 06 Avalon Limited with 3,500 miles. Living in the Ozarks, I usually use the "manual" mode as I go up & down the hills leading to our sub-division. The other day I left it in the auto position and after slowing down and checking for traffic, I stepped on the gas and the RPM's shot up to over 3,000 and the car then lurched forward. Need less to say I was thankful that there wasn't any on-coming traffic. this happened on my way to the dealer to get the oil changed. Since that episode, it has happened on 3 other occasions--all while in the auto mode and after slowing down and then stepping on the gas to go. Of course, the dealer couldn't duplicate. I found a website for those who want to complain to the National Highway Transportation Safety Agency (NHTSA)) The website is www.mycarstats.com--you can view complaints to the NHTSA on any number of cars. NHTSA website is www.nhtsa.dot.gov There IS a problem with the auto trans and before someone gets hurt, Toyota needs to address the issue--so here's a great avenue to let your feelings be known.

doxon · June 2006

I'll look into that website. The jerking and just plain over reving occurs a few times per day with my 06 limited. All Toyota will tell me is that I need to learn how to drive the Avalon. They have a document that spells out exacly when and when not to "ever gently" press the accelerator in specific conditions. What a joke.

bobwiley · June 2006

doxon: The F-150 I traded and my wife's Grand Cherokee Ltd "NEVER" had transmissions do anything like what I experienced with our Limited. In fact, I've been driving over 50 years and other than a "slipping" automatic, I have never experienced anything like the Avalon's quirky tranny.. Love the Avalon--however--from now on, I'll be very skeptical about stepping on the gas--unless--I get the "Tell it All" document from Toyota on how to completely change my driving habits to "learn how" to drive an automatic the Toyota way! What a CROCK--Toyota has a "major" problem with the Avalon tranny and the more people who report this through the NHTSA the better.
Bob

magrezza · July 2006

I have to agree--and disagree. I am 42, have owned about 16 cars since I was 16, and own an '06 Avalon Limited, early production model. YOU DO HAVE TO LEARN HOW TO DRIVE THIS CAR. I am not saying that it should rev to 3,00 rpm suddenly, which is possibly another issue, altogether. At the same time, due to the way this transmission is programmed to give exceptional performance, combined with outstanding gas mileage, it is a bit tricky at first.

These are my suggestions.

1. Never drive in "stop and go" traffic in the "auto" mode--I always use "2". The reason is that your transmission will re-program itself, interpreting crawling motion as a "driving habit", which no one has. In my case this effect is worse, since I am, admittedly, an extremely agressive driver.

2. Learn when the transmission shifts automatically, and avoid accelerating in city traffic if it about to downshift. This is what causes that "herky-jerky" feel. Try to always wait for shifts BEFORE pressing the accelerator. For example, if you are slowing down/braking, and then need to suddenly accelerate, if the car is about to downshift, and you press the gas, it will jerk forward.

3. NEVER, EVER put anything less than 91 octane in this car. 93 is better, and preferred, and will improve driving experience NOTICEABLY. For you money misers who are too cheap to by premium gas, I honestly suggest selling the car, and buying something else. This makes a MAJOR difference. I was forced to buy cheap gas one day, and felt as if I had changed my car, as it was jerking all over the place, and completely unable to shift smoothly. NEVER 87 OCTANE. NEVER, EVER.

4. If your driving style is very passive, the "herky-jerky" effect is worse. The tranny shifts very early, and often too soon. Consider accelerating fast every once in a while, to keep shifts more delayed. Remember, this car is smarter than you are, and knows what you do, a WILL second guess your driving.

5. In time this does get easier. I was frustrated when I first got my car, but now, after about 8K, I don't even notice shifting.

All of this might sound like too much trouble, however, I have never, ever bought a car that I didn't have to "learn" to drive--BMW, Mercedes, VW, etc. Remember, these are machines that are not perfect. Get to know your car, be patient, and, it will get better.

Last of all, on another subject. I THREW OUT MY CRAPPY MICHELIN TIRES LAST WEEKEND, and put on Yokohama Advan S4's, 225/55/17. I FEEL LIKE I HAVE A NEW CAR. Traction is dramatically better, I can corner faster, and the car drivers more like a BMW or Mercedes. I had them up to 115 mph last week on the highway (for only about 10 seconds), and the car felt as stable as if it were at 50 mph. Toyota is cheating us with such crappy tires on such a great car.

wwest · July 2006

Remember the engine/transaxle hesitation issue...??

We all wanted a fix, right...?

Well...

Now it appears that the engine/transaxle ECU firmware has been modified to allow the engine torque, revs', to rise even if the transaxle clutches have not fully and/or firmly seated.

Toyota/Lexus was telling us that the engine/transaxle delay was in place to "protect the drive train" (allow additional time for the transaxle's clutches to fully and firmly seat during times of "unexpected" downshifts).

Now they have shortened the delay.....

Insofar as the need higher octane being somehow related, a cure, for these transaxle delay and/or over-rev problems I wonder if the DFI engines are being introduced to solve that issue once and for all.

All I can see as a result of using higher octane fuel is less need for downshifting, or "deeper" downshifting, when the car is caught, inadvertently, in a higher gear than appropriate for the current, "new" circumstance.

bobwiley · July 2006

magrezza: Understand your thoughts--but---I'm 62, I live tat Lake of the Ozarks, don't drive in stop & go traffic, its 12 miles to town and thrre's 1 traffic light. I use 89 Octane gas and get 27 MPG local and 30 Hwy. Maybe on my trip 15 July I'll try 91 and see what happens. Like I said in my forum--I did usually use the "manual" mode when going down the hills leading to and from our sub-division. I was just sahocked when I left it in the auto mode and the RPM's shot up to over 3,000 and the car lurched forward. I still don't feel as though after driving for over 50 years--both auto's and manuals--I should have to "learn" how to drive an automatic--I bought an automatic so I don't have to shift. I do love the manual mode and it is a very nice addition. I have 3,500 miles (bought 26 Jan 06) and while overall this is the finest car I've ever owned----including Caddy's, Lincoln's & Volvo's, I do have that lingering worry--will the tranny surge at a critical time? I expect 80K miles from my Michelins---what is the estimate on the mileage for the Yokohama's? Thanks for you input--that's why I like the Forum---diverse ideas and opinions!!
Bob

9119911 · July 2006

I have complained to dealer on three occasions with the same transmission hesitation problems (06 Avalon,2,000 mi.)you're having,each time they said they could not duplicate problem. My opinion is the technicians and service manager are trained to give that reply,but, what they really ought to do is think!!! our time is more important than complaining about something that they say they can't duplicate DUHHHH!
I advise each person that has this problem to complain by using NHTSA @ NHTSA.GOV and in the meantime continue to leave your car with the dealer time and time again. Georgia has a lemon law that can be imposed after three (3) complaints with no fixes.

Good Luck,
Cj

wwest · July 2006

Late in the last century there was a paper written and published by Sierra Research (I think) on how car manufactures might use existing technology and mechanical capability to improve FE as much as 9.8%

This proposal involved ASL, Aggressive Shift Logic, upshifting the transaxle whenever feasibly possible. Getting into a higher gear ratio "more" quickly will always result in lower average engine RPM and thereby improved FE.

Torque converter must be "lossy" by design, to supplant the need for a clutch the torque converter MUST NOT couple very much energy to the driveline at low engine RPM levels. So using the torque converter lockup clutch more often, to eliminate those losses, will also result in improved FE.

So, as of about the year 2000 Toyota began adopting these techniques.

That resulted, at times, in the gearbox NOT being in the most appropriate gear ratio for what the driver's next intentions might be, became.

As you come slowly to a stop the gearbox upshifts (feels as if being bumped slightly from behind) and then doesn't downshift into 1st gear until you have come to a full and complete stop.

And if you change your mind, now that the gearbox is in 3rd, before coming to a full and complete stop?

For the RX series prior to 2004 the gearbox would react always quickly and downshift simultaneously with the rise in engine RPM. These had a solid connection between the gas pedal and throttle valve.

As we all already know the earliest inceptions of this ASL technique, the 1999 RX300 for instance, is resulting in premature transaxle failures. Pretty rough on transaxle clutch frictional surfaces to have the vehicle be almost stopped and have the engine output torque level start rising rapidly while in 3rd gear and have to downshift into first quickly.

Burn baby, BURN!!

Sorta explains why ATF needs to be flushed every 15,000 miles, doesn't it..?

So, the 2004 and after RX330s (and others...??) get a DBW system to "protect the drive train", prevent the engine torque level from rising until those clutches can be fully and firmly seated.

Lots, loads of customer complaints result and not just a few written complaints to NHTSA.

What to do, WHAT to do.

Well, lets just change the firmware back so the engine RPM rises to the level desired by the driver as quickly as the driver can apply pressure to the gas pedal.

So now here we are at 2006 with 2007 models either here or on the horizon and the new engine/transaxle firmware has been adapted to eliminate the engine hesitation/delay effects.

In other words...

BURN baby, BURN.

With transaxle space so very limited in FWD vehicles just how small must those clutches be made in order to have 5-speed or even 6-speed transaxles?

Maybe Toyota has looked in to NASA's dust bin and found a clutch frictional material that will last for over 100,000 miles with the engine going "overspeed" during gearbox downshifts.

Or...

The engine hesitation/delay was deemed too hazardous to humans to warrant using it to preserve those clutch surfaces. Better to continue replacing transaxles than incur the publicity of producing cars that are clearly hazardous to the driving public.

kbondar · July 2006

IMHO, such is comedy:

Maybe Toyota has looked in to NASA's dust bin and found a clutch frictional material that will last for over 100,000 miles with the engine going "overspeed" during gearbox downshifts.

Or...

The engine hesitation/delay was deemed too hazardous to humans to warrant using it to preserve those clutch surfaces. Better to continue replacing transaxles than incur the publicity of producing cars that are clearly hazardous to the driving public.

Maybe comic relief was intended as a break from routine speculation?
That said, if it was a serious statement, how/why/where/to what extent would it qualify as "seriously hazardous to the driving public"? What an alarming condemnation, especially with no evidentiary substance anywhere on record!!!

oilcan2 · July 2006

Rented a Av. in chicago for a week decided we could live
with the trans if we buy a AV.
Here are some observations on above posts.
Premium gas burns slower than reg.,The es300,es330,and their camry counterparts have different epa ratings with
identical drive trains,my question is what is different in
these cars?,the gearing,the engine tuning,the fuel recomendations?
Do these cars come with synthetic atf?If not has anyone
tried amsoil or some other synthetic in the trans?
This would be worth a try for the posters having the most
problems.
I have used syn.for years in different atf's and found the
shifting to be quicker.
For those debating whether to buy a 06 or 07 AV the 6 speed
has 20%(trans) fewer parts,that would be a factor to consider.

magrezza · July 2006

Bob,

As I mentioned in my post, my comments are apart from your obvious problem of over-reving. I have never experienced anything of the sort, and, if I did, I'd be quite upset, as I'm sure you are.

That being said:

1. If you have the same tires I did (Michelen MXV?) you are being cheated. Those tires are poorly rated all over the Internet, and do not do this car justice. I consider myself to be a driving enthusiast, and don't care how long my tires last. I have never driven one set more than 25K, and always "toss" stock tires when I buy a new car, with the exception of a BMW and Mercedes, which came with excellent tires. With my old tires, I experienced the "anti-lock experience" from time to time, yet, never once with the Yokos--my braking has improved, cornering dramatically more stable, and body roll reduced by about 30%--estimate based upon speed I can take known curves without roll, as opposed to before. They tell me I will get 30K aggressive miles out of them, which is fine for me.

I can't imagine how your car is driving using 89 octane. Trust me, if you put 93, your gas mileage will improve (I can get 36 mpg on the highway) and you will think you have changed your transmission.

I was told when I bought my car not to put anything but premium, and this is the word I've read in many other places. Strangely enough, however, neither the manual, nor the car, indicate this. I would dare say your problem COULD BE your gas. This car is so sensitive to this, that I can tell the difference between 91 and 93. When I used 87, my car would hesitate, and then LURCH FORWARD. No more with 93.

Regards.

user777 · July 2006

WWEST: I still prefer the non-linearity / compliance in the accelerator pedal assembly theory.

If owners are experiencing better drivability by placing more of their foot on the pedal, that would explain a bunch and fits that theory well.

Remember - many owners don't experience these symptoms. Why / how could that be?

I'd be all over a service manager to attempt a fix by replacing my accelerator pedal and/or throttle body assemblies if I had a bad ride.

billran · July 2006

"seriously hazardous to the driving public"? What an alarming condemnation, especially with no evidentiary substance anywhere on record!!

Absolutely correct kbondar. For some reason not completely clear to me, there are people who wish to portray the issue in a way to suggest that it is a huge safety issue and design flaw that affects all vehicles with that drivetrain, which is absolutely untrue. My car and three others I know of personally drive just great. In addition, it appears that there are well over two million cars produced with that drivetrain, yet the total complaints that can be found anywhere total less than 1/10 of 1% of all those cars.

Clearly hazardous? Mines not. And interestingly, the person making these claims neither owns one of these cars, or has even driven one that has the issue.

user777 · July 2006

kbondar, billran,

your position on safety is yours.

factually, just like me, you two don't own a vehicle with hesitation (how wonderful for us) and so your assessment of someone else's safety is based on what, lack of published numerical accident / incident information, or the number of forum entries you've read on edmunds and non-edmunds sites?

If someone experiences some degree of hesitation (i think we can agree from anecdotal information that for some it is non-existant, and for some- it is on the order of a 1/2 second to a second, perhaps more) and communicates they felt their safety was/is compromised in certain driving situations, who is anyone to refute that while being genuine?

To paraphrase you: for some reason, not completely clear to me, there are people who wish to portray the issue in a way to suggest that it is no safety concern.

WWEST nor anyone else is trying to take down the house of Toyota.

If anyone were to read his posts in the totality of the threads he is active in, they would not question his motivation.

kbondar · July 2006

Everyone seems to have an opinion on whether or not it's a afety issue. I thought that fellow was just joking. Really, it's only differences of opinion, not WWIII!!
So far, so good. If you're serious in your beliefs, I think some solid empirical evidence might settle the contention, but there isn't any. Sad, but true. Everyone will just have to settle for opinion.
That said, I have to say that any suggestion re someone trying to take Toyota's house down by expressing their opinion never entered my mind. Surely you jest!! Come to think of it, that's a really wild idea!! Why on earth would anyone think that, let alone grouse about it??

bobwiley · July 2006

magrezza: I'm going to try the 93 Octane if I can find it here at Lake of the Ozarks, I've never looked for it as 89 Octane has worked for me. If I can't get it here, I'm sure I can get it on my 15 July trip to OK City---let ya know what happens! You probably drive far more "aggressively" than me---I had BF Goodrich tires on my F-150 and got 65,000 miles--Joel, my tire dealer told me I still had 10,000 good miles left--I told him, maybe for some--me I want lots of tread!! I know the "lurching" tranny isn't gas--car has plenty of "gitty-up"--I find myself too often with a lead foot--the car is a hoot to drive. I laughed at one stop light adventure as a BMW 530i got a good look at my rear end--ended up he stopped at the same Chinese restaurant--he couldn't believe it was an Avalon Limited--costing about $16K less! The lurching tranny is definitely a problem--far too many people experience it daily. Appreciate your input and I will try the 93 Octane!
Bob

billran · July 2006

For what it is worth I was not questioning any individual's claims, or whether or not they had symptoms that might constitute a safety issue.

What I was questioning was the assertion that the hesitation they experience is "by design" and present in all two million other cars with that exact drivetrain. I base that on my own personal experience driving one for the last year and a half, plus the experience of two coworkers and a neighbor. All of our cars drive just fine. The design, as experienced in our cars, results in smooth quick acceleration. That by no means implies that someone else might not have a problem. But the assertion, as stated above, just does not fly. I do believe however that the NHTSA investigates, and takes action on any true safety issues they become aware of.

wwest · July 2006

for just a moment in time....that the engine/transaxle delay/hesitation is the result of something the ECU is "learning" about the vehicular operating charactoristics, habits, of the driver.

I think we can all safely assume that these transaxles "want", or programmed, to upshift and/or use the lockup clutch as much as possible in order to extend FE and maybe for other reasons. Let's also assume that the firmware design is such that the transaxle is EXTREMELY reluctant to downshift.

How does one go about programming a system that detects certain driver charactoristics and then applies them to the transaxle shift pattern??

Let's take a truly decisive driver for instance.

What would/might that driver do as s/he travels along the acceleration lane wanting for an opening in the upcoming traffic to merge into?

Would a decisive driver get completely off the gas for slight coasting, maybe even apply light braking, and then as a space is "approaching" make a very definite decision by quickly depressing the gas pedal...

On the other hand what might be the actions of an indecisive, not so sure of one's self, driver?

Fully release the gas pedal for slight coasting or dither it on and off? Apply the brakes lightly or heavily??

With a space approaching make an assertive depression of the gas pedal and then hold that position...?

Suppose these transaxles do not so quickly upshift if the ECU has "learned" that this driver is aggressive and almost NEVER comes to a full stop, a California STOP, at a stop sign. Maybe they even "know" to more quickly downshift if the driver has certain traits.

Bottom line is that until we know why these transaxles act this way, seemingly only with certain drivers or specific vehicles, how can we say the problem is NOT in ALL vehicles in the fleet?

kbondar · July 2006

When a "let's suppose" approach prefaces the commentary, how can any definitive conclusions about "an entire fleet" be drawn? The discussion becomes moot right from the start. I think such logic qualifies as trial and error hypothesis, and not much else. But it certainly was creative! Meanwhile, back to the drawing board!

buzz123 · July 2006

I agree with your basic idea that this problem probably exists throughout the fleet and people are/are not experiencing it because of their driving patterns. I'm not a gear head so I can't really speculate on some of the details you suggested. As far as myself, I am a very conservative and cautious driver and do not consider myself to be agressive at all. However, there is a school near our house with speed bumps. As everyone knows, the whole idea behind speed bumps is that you are supposed to slow down without coming to a complete stop and then speed up again. If I am very cautious and slow down to under 10 MPH, without coming to a complete stop, and then accelerate again, this is the exact situation the Avalon transmission hates! The only way to get a smooth shift is to keep my speed over 10 MPH. If I do that, everything is OK. However, this goes against my nature as a cautious driver because I would rather go slower than 10 MPH. I would be very curious to hear back from people that are not experiencing any problems with their transmission to see if they have ever tried going over speed bumps like this, slowing down to under 10 MPH without stopping, and then accelerating again. Since this engine has more horsepower than the previous one, gets better MPG and has a "smart" transmission, I've always thought the transmission problem is due to Toyota trying to get every last MPG they can out of the vehicle by playing games with the "smart" transmission. As I said before, I'm not a gear head so I can't speculate on what kind of things they may actually be doing, but I think the general idea is sound and in general terms agrees with what you're saying. I think the ideal situation for everyone would be for Toyota to add some kind of switch to the system so those of us that don't like the "smart" transmission can turn it off and those that are happy with it can keep it on. Maybe this could happen when you switch from S to D on the gear shifter? D could be "smart" transmission on, S could be "smart" transmission off. It seems that swicthing to S already disables part of the smart transmission. Maybe they could change it so it disables it completely? Toyota could still say they get the same MPG with a note that the MPG may go down if you switch into S instead of D. This way, I could put it in S to switch off the "smart" transmission when I go over the speed bumps and then put it in D to switch the "smart" transmission back on after that. If the switch is too costly, then I would be more than happy to sacrafice a few MPGs for a smooth ride. In my particular case, I would opt for having the "smart" transmission turned off all the time.

bobwiley · July 2006

Folks: I didn't buy a $39K car expecting to have to "teach" it how to downshift properly. Just so I wasn't thinking maybe I'd been "brainwashed" by the Forum regarding the "lurching" tranny. I asked my neighbor, roughly same age--over 62, to drive my Limited on the same course in and out of our subdivision. The only thing I told him was to slow down at the bottom of the hill and then if no traffic was coming to proceed as normal. Guess what, the ole engine rev'd to over 3,000 RPMs and when the tranny engaged, we lurched forward. Really scared him. I took over and drove the same route, only this time I did as I usually do and used the manual mode--no problem at all. On the way back in to the subdivvision, I duplicated the lurch when I left the selector in the automatic mode. BTW--he has a 98 Camry with automatic and over 165,000 on it--NEVER an incident like he experienced! For those who've experienced this quirky tranny--it is scary and needs to be fixed. I dare say that more have experienced it than we know about. Guess I'll have to start "teaching" the tranny--I just worry that it won't learn quick enough and it could put me in a situation where the engine is rev'n , the tranny is lurching and the car is fast becoming an obstacle in the way of on-coming traffic. Maybe I'll just use the manual mode--at least I know the tranny shifts as it sould in that mode. I'm an easy going guy, but, from a $39K vehicle
I do expect a "smart" smooth shifting automatic.
Bob

bobwiley · July 2006

buzz123: Right to the point. You've experieced the same thing as mee--slow down and then accelerate----watch the RPM's an hang on for the lurch. Take away a couple of MPG's--I get 25-27 running around here at Lake of the Ozarks and over 30 MPG highway--on 89 Octane with Ethanol. I read a Forum about using 93 octane and on my trip to OK City this month I'm going to try 93 octane and I'll let the Forum know the results.
Bob

buzz123 · July 2006

bob: You're right, it's the exact same thing. I've had my Avalon for 10 months now. Unfortunatley, the tranny is still the same and has not "learned" its way out of this problem. I definitely agree with you 100% when you said "For those who've experienced this quirky tranny--it is scary and needs to be fixed." I won't even let my wife drive the car for that reason. At least I'm somewhat used to it by now, but I'm always thinking in the back of my head that this thing is going to have problems in an emergency situtaion and it will lead to an accident. I haven't tried the 93 octane. It'll be interesting to hear your results. Good luck with it!

wwest · July 2006

It appears to me that the engine over-speeding is a relatively new (2005/+ ??) symptom/indication of this AURD (Aggressive Upshift - Reluctant Downshift) problem. Starting back in say, 2004, I saw many complaints of 1-2 second downshift delays wherein the engine did not respond at all to the accelerator pedal.

Certainly if Toyota is actually using the DBW to "protect the drive train" then there would be no excuse for the firmware commanding the engine to develop torque, over-speed, until the downshift completes.

But more recently I have begun to see complaints of engine over-speeding during those same "traditional" AURD downshift incidents.

Am I wrong...?

If I'm right I suspect what we're seeing is a "refinement", evolution, of the engine/transaxle firmware.

Maybe Toyota is in the process of refining the firmware where it will be better at predicting which, or when, the driver will wish to soon accelerate rather than cruising along at the current speed or in the other case NOT coming
to a full and complete stop.

I wish them GOOD LUCK...!!

bobwiley · July 2006

buzz123: Where do you live? Do you have any hills and have you tried the "manual" mode? From now on, going down our hills, I'll use the manual mode--I can't wait for the tranny in a $39K car to learn how to properly downshift and be ready to accelerate when I need it. At least in the manual mode when ya step on the gas it goes--no 3,000+ RPM revs on the motor and a lurch when it connects. I remember that sensation in my dad's new 56 Pontiac until he had the transmission repaired. Fix the obvious transmission problem is just what Toyota needs to do---I bought an automatic cause I was tired of shifting---now I have a transmission that has apparently learned to be a shiftless automatic under the SAME condition everytime. Other than the lurch after coasting and then stepping on the gas, the transmission works great. I would imagine that 60%+ of all Avalons sold are to people in the 50-65 age group--so, we're now telling folks who've been driving 30-50+ years they must "teach" their automatic transmission is unbelieveable. It makes about as much sense as telling folks they must teach their TV remotes to learn how they press the buttons. Is an automatic transmission---shift automatically--whether coasting, stopping or accelerating. Hopefully nobody will get in an emergency situation where they expect the tranny to shift properly----but, Ole Murphy is lurking in the area!!
Bob

havalongavalon · July 2006

Hi wwest,

These recent messages seem to describe the same old, same old, occasional RPM surge that has characterized the Avalon since the early 2005 model came out, discussed many times in this forum.

Firmware doesn't seem to have been modified yet or if it was modified, it was apparently not improved.

As you and others have pointed out many times, a complex control strategy and some driver input assumptions are needed to achieve the Avalon's fast acceleration AND high gas mileage. A quirk of this control strategy is an occasional "racehorse" behaviour when stepping on the gas again after having slowed down to a ner stop or down a hill. This gas pedal input has to be VERY GENTLE.

Hi buzz123 and bobwiley,

A higher foot placement on the gas pedal seems to help, because it naturally tempers the magnitude of the foot input. The gas pedal is much more sensitive when depressed in its lower half.

The other thing that seems to temper misbehaviours is to routinely shift to "S" and 5, instead of "D".

havalongavalon

user777 · July 2006

if what you say is true, you should push the service manager to put a new accelerator pedal assembly including sensor in the car.

havalongavalon · July 2006

The issue is not a defective pedal assembly, it is a characteristic of the current pedal design. I believe the gas pedal could be designed differently to reduce this effect, but if so, it is up to design engineers to do this; not service managers.

havalongavalon

buzz123 · July 2006

Bob: I'm in New York State and we do have some hills in the area. I have tried the tranny in "manual" mode, and you're right, it's definitey better than "regular" mode especially on the hills. However, I still have problems when I go over the speed bumps whether I'm in "manual" mode or "regular" mode. I know what you mean about waiting for the tranny to learn how to downshift. It's been 10 months for me and it still hasn't learned how to do it right, so I'm not very hopeful that it ever will no matter what I do. I've never had a transmission that behaves like this before and I hope I never have another one that does. I think that's a very good analogy you have about the TV remote. There's no way people would settle for something like that so there's no way we should have to settle for something like this, especially since it has the potential to cause an accident.

Havalongavalon: As mentioned above, I've tried using "S" and it helps somewhat. It works on the hills, but not on the speed bumps. However, I have not tried the foot placement. Thanks for the suggestions!

Buzz

wwest · July 2006

It seems pretty obvious that owners who "adjust" their foot position on the accelerator pedal have positive results.

Putting your foot pressure higher up on the accelerator would undoubtedly require more foot pressure for a given pedal/throttle position. If a given driver tends to "dither" the accelerator pedal then that effect would be substantially reduced as your foot moves farther up the pedal.

That would indicate to me that the indecisive, somewhat hesitant, driver would be the one most likely to experience this problem.

bobwiley · July 2006

Guys--isn't it amazing that in 2006 we have to "re-learn" how to put our foot on the gas peddle and "teach" our automatic transmission how to properly shift!! Mmmmmmmmmmm--makes ya wonder if I'll have to use my left hand vs right hand to open the frige!!! Or maybe the frige and microwave will conspire to "un-learn" all I've taught them!! Nuff sarcasm--maybe?!!
Bob

havalongavalon · July 2006

Exactly, wwest.

I think that this situation may be compounded in the 2005+ Avalon because, in my view, the BRAKE pedal requires fairly HIGH pressure, whereas the GAS pedal requires very LIGHT pressure for average driving conditions, compared to my previous cars.

This means that in stop & go driving, when you frequently switch your right foot from gas to brake to gas again, you need to continuously re-calibrate your foot pressure depending on which pedal you step on.

Clearly, most drivers are able to naturally and automatically adjust their foot pressure depending on whether they step on the gas or the brake pedal. But for some drivers, this may be a more serious challenge. Conceivably, an indecisive or inattentive driver could at some time come off the brakes and step on the gas way too hard, and this would cause an unintended surge in RPM. Stepping higher on the gas pedal helps reduce this excess pressure.

One suggestion for improvement for 2007 (probably too late for the first 2007's since they may be already in production; but could be implemented at any time): re-design the gas and brake pedals so that their pressure requirements are more closely matched (make the brake pedal somewhat softer and the gas pedal a little stiffer).

havalongavalon

havalongavalon · July 2006

Bob,

You chose a good example. Do you need to use the same strength to open your fridge door and microwave oven door? Or to close them? Probably not. And, probably you have unconsciously adjusted to these differences, and you apply the right amount of force to each. But sometimes you may forget, and yank the microwave door, or slam it shut -- ever happened?

Yes, we have to learn how much pressure to apply on any car's pedals. These properties can vary quite a bit.

Just like the pull that you clearly can feel from fish of different sizes will vary! (Yes, I thought that this would hit home!)

havalongavalon

user777 · July 2006

i've read what you've written w.r.t. the pedal pressures and re-design and do not disagree. however some people indicate they have no trouble... and i do not believe this is all explained by drivers learning how to drive their toyota.

i'd like to know if a problem car has a non-linear pedal position sensor (dead-spot), or if it has enough mechanical play on the low end that a position change isn't sensed by the sensor.

Toyota Avalon 2005+ Transmission Questions

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