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Reverse gear whine has me curious...

Discussion in 'Technical Chat' started by TacoinSC, May 27, 2008.

  1. May 27, 2008 at 10:33 AM
    #1
    TacoinSC

    TacoinSC [OP] I'd rather be in Jamaica...

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    Being this is my first Toyota, I've noticed a distinct whine when using reverse. Makes a "wind-up" kind of noise. Come to think of it, I've noticed this on a lot of Toyotas, old and new, which leads me to believe it's completely normal.

    I'm not concerned by it, just curious: what causes it? Is it the way the gears are cut?
     
  2. May 27, 2008 at 1:22 PM
    #2
    TacoinSC

    TacoinSC [OP] I'd rather be in Jamaica...

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    Never mind. Found the answer:


    "The teeth on gears of mass market automobiles are not straight-cut, but are helically cut, in order to reduce gear whine. Reverse gear often is straight-cut, however, leading to a characteristic whine from many cars when reversing."

    Excerpt taken from:
    http://www.spiritus-temporis.com/manual-transmission/internals.html
     
  3. May 27, 2008 at 5:41 PM
    #3
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Staff Member

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    FlimFlubberJAM
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    Good job! Its correct. Most all vehicles will whine in reverse. :)
     
  4. May 27, 2008 at 6:52 PM
    #4
    TacoinSC

    TacoinSC [OP] I'd rather be in Jamaica...

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    The Tremec T-56 in my GTO has constant mesh synchronized reverse, I guess that's why you can't hear it. Why do you think Toyota (actually Aisin) uses straight cut gears for reverse? Cost savings?
     
  5. May 27, 2008 at 7:00 PM
    #5
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine. Staff Member

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    4.10 gears, sliders, and lots of buttons.
    More than likely. Other manufacturers use a straight cut gear for revers as it is narrower than the other gears, and allows them to save a little space and weight. :)
     
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