Howl Noise When Taking a U-Turn and Accelerating a Little

Discussion in 'Mechanical Problems & Technical Chat' started by Only Human, May 15, 2017.

  1. Only Human

    Only Human Well-Known Member

    Messages:
    20
    ' 14 Civic Si @ 32k miles.

    When taking a U-turn, with steering wheel at or near full-lock, while in second gear, and accelerating a little, I get a howling noise from the front of the car.

    Sound is similar to that of a hydraulic power steering at full lock, but it only happens when as described above. It does not happen when turning without accelerating. It also doesn't happen when accelerating hard.

    The howl is like a differential or bearing noise.

    Has anybody noticed this sound when for example taking a U-turn and you're being rather quick than a gentle turn?

    Or could somebody please test this out?

    Thank you very much!
     
  2. Redrocket1

    Redrocket1 Well-Known Member

    Messages:
    141
    Location:
    Kalamazoo, MI
    Vehicle Model:
    Civic Si
    Body Style:
    Coupe
    My guess is that your limited slip differential was doing its job. I found this video which explains how they work:

    View: https://www.youtube.com/watch?v=WeLm7wHvdxQ

    But it looks to me like the friction discs in one of the clutch packs were slipping, as they are supposed to, and maybe made a noise because they're breaking in.
     
  3. Only Human

    Only Human Well-Known Member

    Messages:
    20
    Thank you for following up Redrocket1. That's what I was imagining and hoping too, but after your post, I looked more into what "helical limited slip differential" is and unfortunately, it is an all-gears based system than a clutch based system.

    I must have a noisy gear somewhere unfortunately. Have you noticed such a howl ever at all?
     
    PainlessCandy likes this.
  4. webby
    • Staff
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    If you can replicate the sound all of the time I'd take it to Honda and show them the noise on a test drive. You're under warranty so it'd be free.
     
  5. Only Human

    Only Human Well-Known Member

    Messages:
    20
    Yeah, it is fairly consistent but variables need to be pretty spot on (light acceleration, little less than full-lock).. I got an appointment on Friday.

    I keep my car in pristine condition. I hate that this is happening.
     
  6. Only Human

    Only Human Well-Known Member

    Messages:
    20
    So yeah, the dealer didn't hear anything. I don't blame them too much because once the car is hot and it's hot outside, you can't really tell the noise is there if you don't know what you are listening for. But in the mornings in cooler weather, even with the car warm, it's 10 times more prominent and very obvious to hear. I made another appointment for Tuesday morning of next week to try replicate it myself.

    I do blame them though for making me sit and wait 1.5 hours without saying anything first.
     
  7. webby
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    You own a GoPro, or can you get someone to ride with you and record it on video from even a cell phone?
     
  8. PainlessCandy

    PainlessCandy Well-Known Member

    Messages:
    250
    Location:
    Cleveland
    Vehicle Model:
    Civic Si
    Body Style:
    Coupe
    From the research I have done, our Si's have a Helical LSD which does not use clutch packs or otherwise work like the video above, so I'm wondering if that's actually what it was. They are completely mechanical and don't use any friction surfaces inside. The Torsen LSD is one kind of Helical LSD, but is slightly different from the one used in our cars. This video gives you an idea of how it works.


    View: https://youtu.be/lZmsY2YvVsc


    Sent from my SAMSUNG-SM-N910A using Tapatalk
     
  9. FF MAYHEM

    FF MAYHEM Well-Known Member

    Messages:
    171
    Location:
    Tennessee
    Vehicle Model:
    Si
    Body Style:
    Kouki
    It's the diff
     
  10. Only Human

    Only Human Well-Known Member

    Messages:
    20
    Hey everyone, thank you all for following up! And PainlessCandy, thanks for the video; I've been looking for an animation of the helical LSD for a while. I found an Integra forum where somebody had a picture of the helical LSD, which was very similar in principle to the video you posted. Main difference I think is that the one in the video is for RWD, and ours is FWD differential.

    First of all, the summary: I changed the MTF and the noise completely went away.

    Long story:

    I took it back to the dealer and the service manager heard and recorded the noise but told me that the noise needs to get much louder before he can diagnose it up on the lift and told me to keep driving it. I asked him if changing the MTF would help and he said that they never work on manual cars anyways and the MTF shouldn't need changing. He also didn't seem knowledgeable about Si's and LSD's.

    Then, I ran into Scotty Kilmer's "Howling Honda" video on Youtube where he says that the CRV rear LSD's are notorious for a howl during sharp turns and the fix is to change the differential fluid. After seeing that video, I did more research and came across Honda Element forums where people said that after changing the MTF, all kinds of weird noises went away. I also saw more people talk about CRV noise getting fixed after the differential fluid replacement.

    So, even though the Honda MTF and the Dual Pump II differential fluid are different stuff, they both are gear oils for Honda LSD's. I was determined to replace the MTF on my car.

    What drained out was a very dirty MTF. Even though the fresh Honda MTF has a dark oily red hue to it, what came out was practically black, even in a white, Dollar Tree drain pan. Luckily though, there were no chunks of any kind. It's been 4 days since I replaced the MTF and there is no noise. Now, I have no idea why the MTF was so dirty, but I used to use engine brake excessively, so I stopped doing that. I don't otherwise abuse my car.

    Changing the MTF was as easy as changing the oil. I cut the flap of a large cardboard box, folded into a vee, wedged it between the transmission and the frame, and let it sit in the drain pan. When I removed the drain plug, the gear oil just hit the cardboard and went straight into the pan, without making a mess. I then refilled the transmission from the top fill hole, under the air filter box. The filter box comes off pretty easily after pulling on it hard (harder than you would think).

    I would highly recommend changing the MTF relatively regularly. I plan to do it again so to flush out the contaminants and then do it every 15k or so.
     

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