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Lexus RX 350 Driving Experiences and Problems



  • wwestwwest Posts: 10,706
    The F/awd system in the new 2010 RX350 (also the new venza, and the 2011 Sienna) is entire different from the totally useless F/awd system in you (and my) 2001 RX300. The new F/awd system is a virtual clone, knockoff, of the Ford escape, Mercury Mariner, Mazda Tribute, and Mazda CX-7.

    The CX-7 seems to be the only one of these not having poor relaibility of the PTO, Power Take Off, system. The CX-7 uses liquid cooling, engine coolant, to handle the heat load of the PTO when the rear drive is engaged.

    I would suggest finding the fuse for the rear drive clutch and removing it to see if the noise doesn't abate. With the fuse removed you will not have engine torque to the rear wheels but this time of year that may not much matter.

    Having a solid level of drive to the rear simultaneously with the front will put a serious torque loading on the PTO in certain conditions. The RX350 only engages the rear drive clutch under three circumstances.

    A.) During acceleration in order to divert, apportion, some of the high engine torque across all four wheels thus preventing loss of traction, and thereby lowering the potential for an accident arising from loss of directional control. Really lowers the number of times of TC activation.

    B.) During an accelerating turn. Since the PTO stress can become extreme in a tight accelerating turn the level of torque coupled to the rear will be moderated, LOWERED, via PWM, duty-cycle, modulation. The tighter the turn or the harder the level of acceleration the lower the coupling coefficient to the rear drive will become.

    C.) If wheelspin/slip develops due to the elvel of engine torque being applied. All teh literature available indicates that wheelspin/slip is likely to only occur on teh front wheels and as a result while the rear drive will be instantly and fully engaged TC will also activate. With TC activation the engine will be DETHROTTLED, forced down to a virtual idle, while at the same time the brakes will be applied to the slipping wheel(s).

    The literature indicates that while the RX will have the ability to manually engage the F/awd system, close the rear drive clutch system, as long as roadspeed remains below 20mph, neither the Venza nor the Sienna will have that capability.

    The early Ford Escapes, Mariners, etc, had such a feature, manually engage the rear drive clutch but was removed from newer models, I suspect once the high PTO failure rate was "discovered".

    I'm not sure I would buy a new RX350 F/awd absent knowing the PTO cooling is used and I might well modify the system such that it DID NOT engage the rear drive system EXCEPT at my behest, use of the switch to manually engage teh rear drive.

    If it does have the PTO cooling, or such is adopted in future years, I might considered purchasing a new RX350. But I would immediately set to work converting it to FULL TIME RWD with PART-TIME R/awd(4WD) capability. Drop a front halfshaft and apply 12 volts to the rear clutch, result...RWD. Reconnect the front half-shaft and have a PART-TIME 4WD.

    Drop the front half-shaft and the 12 volt source, result...TOAD.
  • aresrocaresroc Posts: 6
    We bought the Canadian build '10 RX350 with FWD just recently. When compared to the RX330, RX350, this new '10 model's transmission is very load. Louder than any other car we had.

    During acceleration, it gets very noisy. ;-( I would shift the car into neutral while cruising, and rev the engine a few times to see if the noise is coming from the engine. The 3.5 v6 engine is whisper quiet after it is warmed up, but not so for the transmission. This is even the FWD version!!! :surprise:
  • jogan1jogan1 Posts: 11
    I have a 2010 RX350 with FWD purchased in late December that has about 2,500 miles on it and the transmission is not loud at all when new or currently. It performs the same as the 2007 RX350 I had. Have you discussed the loud transmission issue with the dealer you purchased from?
  • wwestwwest Posts: 10,706
    While it's rare for a new car you may have a CV joint on the verge of failing, noise on acceleration, especially accelerating into a turn, would indicate so.
  • aresrocaresroc Posts: 6
    This is like a hollow humming noise. We brought it to the dealer, and test drove the other RX350's they have on the lot. The service person said the noise is noticeable, but it also exists on the other RX's they have as well. :-(
  • My AT&T Tilt will pair with the RXs bluetooth system, but then it disconnects suddenly. This same phone worked flawlessly with my Audi Q7 and still works with my wife's 2008 RX. Does anyone have any insight into this problem?
  • rxrxrx3rxrxrx3 Posts: 8
    edited April 2010
    I just called to schedule my 1000 miles checkup and the dealer said that they just changed it to 5000 miles because the oil is synthetic. Has anyone else been told that?

    Also I noticed that someone is suing because their 2008 RX350 accelerated and caused a serious accident. Apparently not even the 2010 has any brake-to-idle override. And yet such features are put into other cars. - gainst-toyota-for-death-of-their-five-year-old-son-in-lexus-sudden-acceleration-- - incident-2010-03-18
  • aresrocaresroc Posts: 6
    Was told the '10 RX350 have a 10K interval, which is unique among Lexus because you first have a 5,000 mile check-up (without oil change), then you have another factory covered 10,000 mile check-up and oil change.

    I would never worry about "unintended" acceleration. It's been known among many of us that a car's brakes out powers the engine significantly. There is a reason you can stop a car in a much shorter distance than it takes the engine to bring the car to the same speed the braking started. Typically brakes can produce 500~1000 HP of stopping power, and your RX350 engine can do 275HP. The current issue of Motor Trend has an article on this ;-)
  • bobbassbobbass Posts: 34
    edited April 2010

    You are correct in that statement, but AOL & Consumer Reports just posted a story and excellent video on this showing that if you lift your foot off the brake even once during an "unintended acceleration full-throttle incident," you lose braking power. I had read about this and understood the principle, bvut they actually demonstrate it in a 2010 Avalon.

    This will be a very worthwhile five minutes spent. And, see if you catch the "misspeak" at 3:57. You don't have to READ the article, just scroll down and watch the video:

    AOL/Consumer Reports on Brake Override
  • avery1avery1 Posts: 372
    What is the link to the video?
  • bobbassbobbass Posts: 34
    Sorry if that didn't work. Here's the direct YouTube link:

    Consumer Reports Video on Brake Override
  • wwestwwest Posts: 10,706
    "...It's been known among many of us..."

    Then many of "us" are wrong.

    With RWD and without ABS you're more likely right than otherwise.

    With FWD and ABS the likelihood of your being wrong might be in the range of 90%

    Holding a car stopped at WOT and the brake fully applied will almost always work.

    Starting out braking at 60-70MPH with the engine at WOT might be, in most case will be, an entirely different story. As a matter of physics once in motion your primary braking effort will ALWAYS be expended at the front. Note how ROBUST your front brake system is in comparison to the rear.

    With FWD and a WOT runaway engine DRIVING those front wheels the brakes must not only overcome INERTIA but also the engine HP/torque. And in the meantime ABS will be limiting the rear braking effectiveness, perhaps severely so.

    How soon do you think you might encounter a serious level brake fade and even brake fluid boiling in those situations. ..??
  • rxrxrx3rxrxrx3 Posts: 8
    edited April 2010
    Yes, it seems that the brakes won't always work as desired unless applied in a specific way. See recall bulletin link below. And then, as has been commented, given the inertia coupled with the motor and other factors, who knows what the real world result would be. I for sure wouldn't want to be heading into the back end of a semi because of unintended acceleration - even if de-accelerating afterwards.

    In this recall bulletin: - 00122.pdf

    ...they say "If you need to stop immediately, the vehicle can be controlled by stepping on the brake pedal with both feet using firm and steady pressure. Do not pump the brake pedal as it will deplete the vacuum utilized for the power brake assist."

    They also say to hold down the start/stop button for 3 seconds to turn off the motor.

    Can they not update the software to include a program to override the throttle when the 2 are active. I've heard that is undesirable to override if you need both at the same time, such as when stopped or parked on a steep hill. But surely they can do it so that it only overrides when the throttle or idle is in the extreme. I've never had to fully rev an engine to overcome some roll back on a hill, as the slightest rev will do that.
  • rxrxrx3rxrxrx3 Posts: 8
    edited April 2010
    I'm confused. Is a brake to throttle override being added to existing cars under a recall, or just to newly manufactured ones?

    If it's being added to existing cars, while being asserted that there is no known electronic acceleration problem - then it is apparently being added as a safety precaution.

    And if that is the case, why don't we RX owners matter or count? I bought the RX because it was not listed in the recall. But now I'm thinking I'd be better off had it listed.

    So I think I'm going to complain... where ever I can. If they are adding brake to idle overrides to other models - just to add a factor of safety - then I think we RX owners deserve as much too.
  • wwestwwest Posts: 10,706
    "..Can they not update the software..."

    But what if it's the software itself that's causing the engine runaway condition, trapped in a tight instruction execution sequence, Cruise Control "accel" mode, "forever".
  • wwestwwest Posts: 10,706
    Adding BTO to existing car engine control computers would be needless, useless.

    If the computer is for some reason not paying attention to the fact that the gas pedal is at the idle position then why would one think it would still execute a BTO sequence...??
  • rxrxrx3rxrxrx3 Posts: 8
    Why is it logically conclusive that the car isn't paying attention to the idle condition when a car experiences unintended acceleration?

    There's obviously some sort of demand being placed to throttle up. Even if it took a extra detector or interrupt circuit, the logic would simply be (Brake) AND (High Throttle) = Throttle Interrupt; and what is wrong with that?

    My point was, however, that if they are actually adding Bake to Idle Override to other models - then why not also add it to the RX?

    If the logic is that RX has had less problems - then that is not good enough.
  • wwestwwest Posts: 10,706
    Not conclusive, just no reason not to cover all bets. A BTO should be designed to be as failsafe, FOOLPROOF system. IMMHO the only way to do that is with a completely separate instruction execution engine.

    Or simple hardware.
  • aresrocaresroc Posts: 6
    edited April 2010
    ""...It's been known among many of us..."
    Then many of "us" are wrong.
    With RWD and without ABS you're more likely right than otherwise.
    With FWD and ABS the likelihood of your being wrong might be in the range of 90% "

    Great video! It simply validates everything I have said, and adding that pumping the brakes will result in a loss of brake power assist.

    It also showed a Toyota Avalon, a FWD vehicle with ABS and 268 HP, WILL stop from 60 at WOT with brakes fully applied. Must be in that rare "10%" :P

    I don't see how an ABS would play into this, besides 'possibly' slightly 'change' the braking distance. If the ABS are kicking in that means the brakes are working.
  • rparisrparis Posts: 368
    1) Do others find the engine a bit loud when accelerating?

    2) My vehicle has the rain sensing wipers. I cannot tell any difference when adjusting the variable control for sensitivity. On another Lexus, but a different style vehicle, I notice a large difference. What have others observed?
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