Lexus RX 400h Transmission Questions

PF_FlyerPF_Flyer Pennsylvania Furnace, PAMember Posts: 9,372
edited July 2014 in Lexus
Discuss transmission issues with your RX 400h here.


  • hsvdochsvdoc Member Posts: 1
    I have had my RX 400h for about 3 weeks and have logged 600+ miles. When accelerating from a stop, there is a noticeable "shudder" a 1-2 seconds after pressing the accelerator pedal as the car starts moving forward. I thought at first that this was just that a hybrid required a different driving style than what I was used to, but I have tried all sorts of variations on accelerating techniques from excruciatingly slow to rapid starts and the problem occurs every time. There is also a similar although less noticeable shudder when the speed passes the low 40 mph range. Are these normal, and have others noticed anything similar? I have tried to notice if the startup shudder occurs when the gasoline motor kicks in, but I am not sure. I keep hearing how smooth this transmission is supposed to be, but I am not impressed, especially if this is a "normal" characteristic of the hybrid system.
  • lonlin68lonlin68 Member Posts: 11
    I have noticed the "shudder" right after starting to accelerate also. What I think it is (but I'm not sure) is the rear electric motor kicking in for a few seconds. If you watch your Energy screen, I think you'll see this is happening when the rear motor kicks in.

    My thoughts as to what is happening at 40 is that the control unit is switching between using the front electric motor to help drive the SUV and using it to charge the battery. Again, look at your Energy screen and around 40 there seems to be a lot of switching between those two modes. I am not a mechanic; but it makes sense that if the motor is helping to move the SUV and in a second it shifts to charging the battery and not helping with powering the SUV, that this could result in a slight shudder.

    However, some people have reported a more sever shudder at 40. If yours is more sever, you should check out the other threads that discuss that problem.
  • shaftershafter Member Posts: 1
    My RX400h does the "shudder" thing upon takeoff, but I have not noticed any additional "shudder" at higher speeds.

    However, I noticed that the engine "races" disproportionate to the speed increase when pressing the pedal even semi-aggressively. It is though the CVT is slipping. I drove another RX400h recently that does the same thing, but a lot less. My dealer tells me that my car is within specifications. I would like to hear others' experiences, please. Thanks
  • apg97ssapg97ss Member Posts: 21
    We have about 700 miles on our rx400h awd and just did first extended highway trip. we are getting a very disturbing hesitation type sensation at speeds around 60+. Even at constant throttle, when going up small incline, engine hesitates (kw meter even takes quick drop) and then it surges slightly ahead. feels like driving into gusty wind storm. This annoying cycling can continue and peddle feels like it lacks power. needless to say very annoyed at this for a $50,000 car. i will take it to dealer this week. if they say it's 'within specification,' i will hold up a finger and say 'specify this.'
  • skyoatskyoat Member Posts: 1
    My 2007 400h- when I put on reverse, the car went forward. This car has only 25,000 miles on it. This had happened 3 times over last 3 days. I have to turn off the car then on again to resolve the problem. I took the car to the Lexus dealer and they couldn't any problem with it. Does anyone has similar problem with a hybrid model. My 2004 Rx330- has no problem at all after all these years.
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