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Lexus RX Transmission Problems

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  • wwestwwest Posts: 10,706
    Key wording...Sorry...

    "Independant shop replaced it."

    Factories oftentimes make running changes, even within the same MY, in component design, more epecially so with firmware coding and "flash" updating.

    So there is NO way for an independent shop to know if a particular replacment transaxle will match, exactly, the design of the one being removed. More importantly what about the firmwave version, revision #, that applies to the engine/transaxle ECU in your vehicle "as shipped".

    Sorry, really, sorry, but take it to Lexus.

    Don't know if this will help, but maybe...

    At least one, possibly two, of the solenoids within the transaxle are used as LINEAR "servo-controllers" but with NO direct position feedback. Before DBW it was not unusual for an off-the-shelf electric solenoid to be used in this manner to control the A/F mixture at idle via teh idle air bypass channel/path.

    The key to this use is that the controlling ECU must "learn", over time and use, jsut what position the solenoid plunger takes for a given PWM, Pulse Width Modulation input duty-cycle.

    In reality the solenoid plunger position is not actually learned, just the results on the controlled parameter for differing PWM duty-cycles. In the case of the idle air bypass solenoid when a new one is installed the ECU must learn the proper, correct duty cycle, for maintaining the idle at a fixed 800 RPM and with the downstream oxygen sensor signal in te corract range. Over time it must "KNOW" which duty cycle to use with the A/C compressor cycling vs not, how much to adjust the duty cycle as a function of IAT signal, etc, etc.

    So your new transaxle may simply have a solenoid that is intermittent insofar as consistently positioning with a given duty-cycle input.

    Good luck.
  • The transmission in our 2001 RX 300 failed 400 miles from home at 101,500 miles, ruining a vacation. It has been serviced by the book at the Lexus dealer where we bought it, including full 90,000 and timing belt and again at 97,500. We had the vehicle towed to the nearest Lexus dealer (150 miles). The transmission has to be replaced at a cost of $4000. Our question is whether to keep the vehicle; will the rebuilt transmission be reliable? Otherwise, the vehicle is in excellent condition.
  • wwestwwest Posts: 10,706
    [quote name='kolkh' post='127828' date='Sunday, Sep 2, 2007 @ 06:24 PM']DISCLAIMER:
    Previous post is not a simple reply – this is actually 11-th edition of “Wwest Mythology”. Previous 10 editions have been discussed and bitten to death in approximately ~1000 posts in a number of forums/sites. I have read some of those. What is the result? See here:

    [url=http://www.siennaclub.org/forum/index.php?showtopic=6921&hl=]http://www.sie- nnaclub.org/forum/index.php?...ic=6921&hl=[/url]

    As if previous discussions do not exist, wwest posts the same stuff again and again and again…
    Like a Big Propaganda Machine, wwest is in a win-win situation: if you start infinite discussions and win – it does not mater, next time he will post exactly the same stuff. If you ignore him – he will flood forums and poor readers would have to deal with it anyway.

    END OF DISCLAIMER[/quote]

    Okay, "teacher" will take a different tact, tactic.

    Do you know how many things in a car simply waste energy....???

    A) Power stearing hydraulic pump when there is no "stearing" to be done. What, 98% of the time?

    And yes, I do know that PS pressure helps "hold" the stearing in a "set" position, but just how much energy does that require in comparison to the HUGE losses?

    The PS must have the pumping capacity/volume/displacement to help, SERIOUSLY help, turn the wheels at or near a dead stop(parallel parking...), all the while with the engine turning only at idle, of maybe slightly above.

    So, 2200 RPM and driving straight down the highway at 65MPH guess how much pressurized PS fluid is simply being bypassed back into the sump.

    Is it any wonder that many cars are converting to electric power stearing, even at the risk of having the solid state electronics overheat and therefore automatically going into a sub-standard power assist mode?

    B] Gear-type engine lubricating pump. Again, pumping volume/capacity/displacement must accomodate full pressure and flow even with the engine at idle. So as engine RPM rises the EXTRA pumping capacity must be bypassed back into the sump.

    Either BMW or MB, don't remember which, has already gone to a variable displacement engine lubricating oil pump in oder to reduce these losses and thereby reduce the engine heat load and also increase FE.

    C) A/C compressor. Here again, the compressor pumping capacity must be such that it can provide FULL cooling capability at engine idle on a BRIGHT and SUNNY 100F (or above) day. In this case the A/C clutch along with a reasonably sized liquid refrigerant storage reservoir has been used for "eons" to ammiliate the effects of continuous engine loading by the A/C compressor.

    So why do you suppose so many new vehicles are coming out equipped with the new variable capacity "swash plate" type A/C compressor, and the compressor clutch?

    Because it is better design practice, overall, to have a continous ~2HP load on the engine rather than an intermittent load of ~7HP.

    [b]Getting the picture..?[/b]

    D) And just what is the deal with the torque converter (hydraulic TURBINE pump, slush pump, etc.), just how lossy is that sucker?

    The slush pump, torque converter, is really required ONLY to act as an automatic clutch. At low engine speeds, idle, the losses are so high that virtually no torque is coupled to the transaxle input shaft. NONE would be ideal, but nowadays you need a clutch pedal for that. The nice thing about the torque converter is that it also acts as a reduction gear ratio at low torque loading. But, that's where the torque converter lockup clutch comes into play. In OD it is highly desirous to have the engine operate at the lowest speed at which it can produce "just" enough torque for the current load factor...roadspeed. So at low engine RPMs the HIGH LOSS torque converter is bypassed by the lockup clutch.

    E) This one is slightly off point but I bring it because if I don't someone else will.

    The engine coolant water pump.

    Almost all engine coolant water pumps are of the centrifical, turbine, type and thereby self limiting insofar as pumping volume is concerned. Obviously there is some "needless" loss involved here otherwise the water hoses would not "swell", balloon, as engine speed rises beyond the point wherein the thermostat will accomodate the pump volume. Other than the current crop of hybrids, all equipped, to my knowledge, with electric water pumps, other manufacturers have already converted to electric pumps, if not altogether then at least apartially so, for the cabin heater.

    [b]Get the picture..?

    No...?[/b]

    F) And finally....

    The gear type ATF pump.

    Like everything else above the most critical situation insofar as determining base pump volume occurs with the engine at idle.

    Hmmmm..

    Let's think this over a bit.

    Just what "work" does the ATF pump have to do with the engine at idle?

    Shifting from park or neutral to drive or reverse is clearly not critical insofar as pumping volume is concerned...

    Upshifting once underway always involves engine RPM well above idle....

    Aha, DOWNSHIFTING....

    So, when does an automatic downshift with the engine at idle or nearly at idle.

    Not for passing, kickdown, certainly...

    But then how about just before coming to a full stop...?

    Or during coastdown periods with the throttle fully closed...?

    In both of these latter instances if the transaxle is to downshift lots of ATF pressure/flow will be required to ascertain the downshift clutches are quickly and firmly seated. Otherwise, with low or marginal ATF pressure these clutches would undoubtedly incur some serious level of slippage and the wear associated thereto.

    So, the engineers say to each other, if we could eliminate just these two instances the ATF pump FIXED capacity could be a LOT lower and that would undoubtedly inprove FE overall while reducing the heat load and clutch wear rate.

    Say, what does a stick shift driver do in these instances. Well as the cars coasts to a stop teh driver would normally disenage the clutch and slip the transmission into 1st.

    Well, we can't disenage the clutch....Can we...??

    Sure can, simply "upshift" the transaxle a few notches, no substantial level of engine compression braking, NO transaxle clutch wear. Who cares if the upshifted clutches don't quickly fully and firmly engage...!

    But what about coastdown periods at 40-30MPH with the engine at idle...?

    Why not upshift then too, who's to notice?

    ________________________________________

    The theory behind the above dissertation arose because I noticed a seeming abiguity between my earlier theory, "protect the drive train using DBW to prevent engine compression braking.'

    Owners have been reporting that while in cruise control the engine/transaxle ECU will actually command a downshift to retard roadspeed going down a hill.

    Me..."What? Downshift a FWD or F/AWD vehicle and actually take advantage of engine compression
  • wwestwwest Posts: 10,706
    Your 2001 RX300's automatic transaxle failed prematurely because of a well known design flaw (see previous post) introduced into the product series late in the last century. Toyota (Lexus) is very well aware of the flaw and the resulting failures and generally will offer to compensate owners, especially those like yourself with "stellar" maintenance history/records.

    According to various posts on the internet in some cases they will foot the entire bill, in others only the cost of the new transaxle and the owner pays the labor.

    I would go back and open a discussion with the dealer on this matter and willingly start a shouting match in the dealer's showroom if they don't offer a substantial level of compensation.
  • ktcktc Posts: 30
    Question, in what model year of RX, Toyota/Lexus fixed the 2001 transmission problem?
  • wwestwwest Posts: 10,706
    Not sure I really understand your question, but insofar as I know the problem began with the '99 RX and still exists to this very day.

    As long as Toyota(Lexus) persists in using the LOW FIXED volume/capacity/displacement gear type ATF pump for FE reasons I don't know if there can be a satisfactory solution.

    Toyota(Lexus) have made many "patches" and various fixes over the intervening 8 years but as yet I don't think they have yet announced a "final" across the board FIX.

    The '99, and possibly the '00, series had premature, 80-100,000 miles, transaxle failures.

    The '01, and likely all the way up to the RX330 series, tends to overheat the ATF to such a level that the scheduled maintenance recommendation for ATF flush/refill was reduced from infinity to 15,000 miles.

    The RX330 came with DBW to prevent transaxle downshifts, "kickdowns", at times when the ATF pressure had been just previously exhausted and no "make up" was readily available due to the low volume pump and engine speed at idle.

    A little noticed aspect of the RX330 series was that the VC, Viscous Clutch, was dropped from the driveline for the entire RX330 product run. IMMHO it is possible this was done to reduce the AWD load on the transaxle.

    There is an indication that the latest TSB, provided, seemingly, only to owners with specific complaints, is solving the problem on the '08 Camry.

    Anyone know the bottom line news on the '08 RX?
  • ktcktc Posts: 30
    The reason I asked that question is that my wife is considering replace her 2001 RX300 with a new one. Maybe I should also look at the Infinite EX-35 next year.

    Thanks.
  • wwestwwest Posts: 10,706
    Yes, the EX35 does look to be a winner. I was put off by the huge blunt nose, in your face, effect of the other Infinity SUVs.

    The other SUV that you might consider is the Acura RDX.
  • sallyksallyk Posts: 9
    I just purchased my first EVER used vehicle, a 2000 Lexus RX300 with 101,000 miles on it. When I test drove it, it was warmed up and ready to go. I signed the paperwork and picked it up the next day. I immediately noticed a lunge when shifting gears (it's automatic) although this literally only occurred through the first series of shifts and then only again when cold. I've told the dealership about it and they're willing to buy it back but I'm just wondering if I should just tell them I want to keep the car but want the transmission replaced (I'm thinking they'd rather buy it back and sell it to another dealership, etc.). They did perform a "transmission service" on it and said if it continues to bring it back. It continues. Any ideas? They want to make this right but I really don't want to return the car.
  • avery1avery1 Posts: 372
    This might be the hesitation that occurs on at least the first RX models. I have a '99 and it happens on mine. We were told that it has to do with controlling emissions. I don't even notice it now. I remember lots of mention of this in the first few years but it seems to have died out so maybe the transmission isn't programmed that way anymore. Maybe you are giving it a lot of gas and due to the delayed shift points it lunges when it finally shifts up to the higher gear. Just a guess.
  • wwestwwest Posts: 10,706
    It appears that the '99 (for SURE) and possibly the '00 RX300 series suffers from premature transaxle failure typically in the range of 70-80,000 miles.

    Even my '01 AWD RX300 was showing symptoms (burned ATF) of a design flaw as early as 40,000 miles.

    I suspect that when the Camry transaxle was initially adapted for the larger and HEAVIER RX series it needed to be BEEFED up here and there and the engineers missed a few "corners".

    Your dealer should be very well aware of this issue and therefore willing to discuss with you any possible alternative solutions.

    You can search for "toyota", "DBW", and "hesitation", for clarifying posts.

    As of the introduction of the RX330 Toyota adopted a DBW, e-throttle system so it could be programmed to "protect the drive train", prevent the engine torque from rising until the transaxle downshifting clutches can fully and firmly seat when you depress the gas pedal enough to "force" a downshift.

    In the meantime the RX300 series is left to "suffer", wear out the clutch surfaces prematurely, since with a "hard" mechanical coupling to the throttle valve the rising of engine torque cannot as easily be delayed.
  • sallyksallyk Posts: 9
    Thank you. I took it in to my mechanic who admitted that he hadn't seen a lot of problems so he checked with his transmission guy who knew EXACTLY what the problem was even before my mechanic finished his sentence. I had my mechanic call the Lexus Dealership and tell him what his findings were (since I don't speak the same language). They have continued to offer to buy the car back (I don't want to give the car back). They told me to pick up the car from my mechanic and await further word. After reading your reply, should I be concerned that even if the transmission is replaced that other parts have suffered because of this problem and that they'll end up "breaking" even though I have the transmission replaced? Should I just let them buy it back? (It's 100% mint interior and exterior and just seems a shame to give back). I'll await further directive. Thanks!
  • la4meadla4mead Posts: 347
    Hi Damsel and others with similar issues on the *1999* RX. After Mr. West's post I wanted to add some information specific to the '99 model from my experiences. The '99 had a few different issues with the original transmissions. If the Lexus dealer is offering to replace the transmission, I think you will have a fine car.

    First, the '99 models do have a TSB (mention Technical Service Bulletin) that the Lexus service department should be fully aware of, as the "valve body" on that transmission was always a problem, and Lexus realized it right away. On my early '99 built in '98, it caused a "slamming shift" between first and second gears, only when the vehicle was cold, and only in cooler weather (I live in a warm climate so it happened rarely). When this continues to occur, it contributes to the premature wear, along with the issues Mr. West mentioned.

    However, when my transmission was replaced with a factory new unit (at Lexus's expense), the new transmission not only does not have this problem, but is a more modern design without the "delayed" shift pattern that Mr. West mentioned. Most importantly, I no longer get the burned fluid indicating the durability is in question, and am now impressed that the new unit will last a long time as long as it isn't abused or left for extended idling to run the air when parked.

    Also, when Lexus replaced the transmission, they checked to make sure nothing else was damaged (like CV joints, etc.) and nothing else was/has been since, except they were kind enough to find a cracked exhaust pipe that wasn't related and took care of that at the same time.

    There is something else which may be what you are experiencing and it isn't a problem. I can't tell from your question. The '99s have a cold shift pattern programmed so that the transmission shifts "late" at about 3000 RPM for second gear when the engine temp is cold (the needle hasn't moved off the "C"), but just drive easily until it warms up. Year 2000 and later don't have this issue. That continues on the '99 even with the modern transmission replacement I had in '04.

    Other than the transmission, Lexus should check for engine "oil gelling" that occurred under certain conditions, but you would have seen blue smoke if that were a problem. Mine, as well as most, has not had this problem.

    If the transmission is good (or especially if Lexus replaces it with a new factory unit) and frequent oil changes and transmission service, you are likely to have a reliable and fine little wagon.

    You can search this forum and the other RX300 forums and find issues people had problems with (especially this same topic) but remember to take those posts within the context that most posts are about problems on any model of car.

    Welcome to the forum, we are looking forward to your input from your experiences.
  • sallyksallyk Posts: 9
    Mine is actually a 2000. This forum is a great deal of help. Thanks to Mr. West and yourself for explaining this to me in understandable terms. I will continue to watch the feedback.
  • wwestwwest Posts: 10,706
    I agree, if the dealer is willing to replace the transaxle (Lexus will probably at least partially compensate) you should go for it.

    There is one more issue you might want to aware of if you live in the "northern" reaches. You might want to google for:

    wwest demist denso
  • Just thought you might find it interesting that my car has been in the shop (at the dealership) for 10 days now. What do you think they're doing with it? I'm not too concerned since I don't have to pay for whatever they're doing AND I'm driving a loaner car...a 2007 RX350 which is awesome!
  • la4meadla4mead Posts: 347
    Well, your service writer should give you updates, however when they replaced mine they took longer than was expected because the dealer tried to get a brand-new transmission, but Lexus only approved a factory rebuilt to be replaced under warrantee. After trying (fully installing and road testing) two rebuilt transmissions available locally which failed to test to their standards, Lexus corporate finally approved a Japanese factory brand-new updated unit. By the time they got approval to order the new tranny from Lexus, they had already had the car for several days. I gladly went along with this, and am glad I did. The rebuilt ones are probably better now than they were then.

    The worst part was that the dealer was out of Lexus loaners when I originally dropped the car off for an "inspection" when the dealer suggested they would replace the whole transmission under warrantee rather than fix it, but I could get an Enterprise rental at their expense.

    That meant I was stuck with the crappiest Neon I'd ever driven. No cruise, no power locks, 3-speed tranny, no "neon" at all, and I didn't think they built them without power windows then, but I had one. So I was glad to finally have my car back with a "new" transmission which they assured me had all the modern updates, since the original design seemed flawed. I think they had the car close to two weeks by the time they were satisfied, and I'm glad we were able to take their time.

    Moral: If they take their time and get it right to earn your satisfaction, and they are providing a nice car while doing it, it's worth the wait. I would expect updates from them after this time, though.
  • I have a 2005 Lexus RX330 with25K miles; Ran over some rebar and blew out my left front tire.(Michelin) Replaced with Goodyear spare. Dealer says uneven tread will damage transmission and I must immediately purchase three new Goodyear's, or four new Michelin's. Same dealer insisted I needed new brakes at 11,000 miles. Totally untrue, so I can't trust him. Any advice will be greatly appreciated. Don't want to throw money away on tires, but will buy them if necessary, of course. Hesitant to drive until issue is resolved. ( I'm going to post this same request on the repair forum, since I'm not sure if this is the right place and need an answer quickly)
  • wwestwwest Posts: 10,706
    Your dealer may not be aware that the RX330 series DOES NOT have a VC, Viscous Clutch, as does the RX300 and RX350. Provided TC doesn't kick in disparate tread depth will not matter.
  • I have been very happy with Mr. West's feedback. If you don't trust the dealership (I seldom do), do some research (this forum is a good one) and start asking around about local mechanics, tire shops, etc. Go to Yahoo's website and use their "local" feature to type in some local businesses that offer service, tires, etc. and see if there is any feedback or reviews on the place. I am very fortunate to have a VERY wonderful mechanic a few minutes away from where I work in Pewaukee, WI. I hate to say it but I think you may be in the process of being taken advantage of. Do your research.
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