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Discuss Corolla Automatic Transmission Shifting in the alt.autos.toyota forum at Car Dealer Forums; Hi All, I have a 1993, Corolla, 4 cyl, 1.8 liter, EFI engine. The car ...
  1. #1
    SlyckTom
    Guest

    Default Corolla Automatic Transmission Shifting

    Hi All,

    I have a 1993, Corolla, 4 cyl, 1.8 liter, EFI engine. The car has
    200,500 miles.

    Here's the situation.

    When I'm driving at all lower speeds and RPMs, the tranny shifts very
    smooth - as if it were new. However, if I'm entering an on ramp or
    otherwise bringing the engine to high speed or high RPM (maybe
    accellerating past 50 or 60)s, the tranny shifts into gear not as
    smooth. I dont want to say it clunks or it shifts hard, because those
    are too strong of words. It just isn't as smooth as during lower RPMs
    and speed.

    After the tranny shifts down in this instance its smooth afterwards
    regardless of speed or RPM...

    Does anyone have insight into this?

    TIA!!


    Tom




    › See More: Corolla Automatic Transmission Shifting

  2. #2
    Ray O
    Guest

    Default Re: Corolla Automatic Transmission Shifting


    "SlyckTom" <tom@slyck.com> wrote in message
    news:vim5d293sspm1m2lbm6cnnl4v56af2b0vq@4ax.com...
    > Hi All,
    >
    > I have a 1993, Corolla, 4 cyl, 1.8 liter, EFI engine. The car has
    > 200,500 miles.
    >
    > Here's the situation.
    >
    > When I'm driving at all lower speeds and RPMs, the tranny shifts very
    > smooth - as if it were new. However, if I'm entering an on ramp or
    > otherwise bringing the engine to high speed or high RPM (maybe
    > accellerating past 50 or 60)s, the tranny shifts into gear not as
    > smooth. I dont want to say it clunks or it shifts hard, because those
    > are too strong of words. It just isn't as smooth as during lower RPMs
    > and speed.
    >
    > After the tranny shifts down in this instance its smooth afterwards
    > regardless of speed or RPM...
    >
    > Does anyone have insight into this?
    >
    > TIA!!
    >
    >
    > Tom
    >


    You did not mention whether you have an automatic or a manual transmission,
    but since you are implying that it is an automatic, I'll give my 2 cents
    assuming that it is an automatic.

    What is the condition of the automatic transmission fluid (ATF)? Is it red,
    brown, or black? What it the level of the ATF?

    Assuming that the ATF level and condition are satisfactory, my guess is that
    the accumulators are worn. Automatic transmissions have a pump that is
    turned by the input shaft, and as engine RPM increases, pump output pressure
    increases. At higher RPM, shifts will be harsher due to the higher
    pressure, and accumulators act as a shock absorber to reduce shift shock,
    kind of like slipping the clutch a little on a manual transmission instead
    of popping the clutch.

    The increased shift shock is not harmful, and is actually a little better in
    terms of internal friction surface wear but if you want to reduce the shift
    shock, a competent technician should be able to change the accumulator
    without too much trouble, as long as there is good access to the
    transmission pan and valve body.
    --

    Ray O
    (correct punctuation to reply)



  3. #3
    SlyckTom
    Guest

    Default Re: Corolla Automatic Transmission Shifting

    Hi Ray,

    Yes, it is automatic. The fluid is in good shape, and its always been
    changed every 35-40,000 miles.

    Just some further info,it happens only when in third gear. There also
    a noticeable, but slight "bump-bump" when downshifting (and a quick
    "bump-bump" when accellerating).

    These patterns have all fix the discription of 'shift-shock' I've read
    about, and otherwise the car drives great.

    Tom

    On Fri, 4 Aug 2006 10:52:57 -0500, "Ray O"
    <rokigawaATtristarassociatesDOTcom> wrote:

    >
    >"SlyckTom" <tom@slyck.com> wrote in message
    >news:vim5d293sspm1m2lbm6cnnl4v56af2b0vq@4ax.com.. .
    >> Hi All,
    >>
    >> I have a 1993, Corolla, 4 cyl, 1.8 liter, EFI engine. The car has
    >> 200,500 miles.
    >>
    >> Here's the situation.
    >>
    >> When I'm driving at all lower speeds and RPMs, the tranny shifts very
    >> smooth - as if it were new. However, if I'm entering an on ramp or
    >> otherwise bringing the engine to high speed or high RPM (maybe
    >> accellerating past 50 or 60)s, the tranny shifts into gear not as
    >> smooth. I dont want to say it clunks or it shifts hard, because those
    >> are too strong of words. It just isn't as smooth as during lower RPMs
    >> and speed.
    >>
    >> After the tranny shifts down in this instance its smooth afterwards
    >> regardless of speed or RPM...
    >>
    >> Does anyone have insight into this?
    >>
    >> TIA!!
    >>
    >>
    >> Tom
    >>

    >
    >You did not mention whether you have an automatic or a manual transmission,
    >but since you are implying that it is an automatic, I'll give my 2 cents
    >assuming that it is an automatic.
    >
    >What is the condition of the automatic transmission fluid (ATF)? Is it red,
    >brown, or black? What it the level of the ATF?
    >
    >Assuming that the ATF level and condition are satisfactory, my guess is that
    >the accumulators are worn. Automatic transmissions have a pump that is
    >turned by the input shaft, and as engine RPM increases, pump output pressure
    >increases. At higher RPM, shifts will be harsher due to the higher
    >pressure, and accumulators act as a shock absorber to reduce shift shock,
    >kind of like slipping the clutch a little on a manual transmission instead
    >of popping the clutch.
    >
    >The increased shift shock is not harmful, and is actually a little better in
    >terms of internal friction surface wear but if you want to reduce the shift
    >shock, a competent technician should be able to change the accumulator
    >without too much trouble, as long as there is good access to the
    >transmission pan and valve body.



  4. #4
    Ray O
    Guest

    Default Re: Corolla Automatic Transmission Shifting


    "SlyckTom" <tom@slyck.com> wrote in message
    news:kignd2l3te24deoqf5qfc5b841k4ct4uu5@4ax.com...
    > Hi Ray,
    >
    > Yes, it is automatic. The fluid is in good shape, and its always been
    > changed every 35-40,000 miles.
    >
    > Just some further info,it happens only when in third gear. There also
    > a noticeable, but slight "bump-bump" when downshifting (and a quick
    > "bump-bump" when accellerating).
    >
    > These patterns have all fix the discription of 'shift-shock' I've read
    > about, and otherwise the car drives great.


    Keep an eye on the condition of the ATF, and if it doesn't bother you, don't
    worry.
    --

    Ray O
    (correct punctuation to reply)

    >
    > Tom
    >
    > On Fri, 4 Aug 2006 10:52:57 -0500, "Ray O"
    > <rokigawaATtristarassociatesDOTcom> wrote:
    >
    >>
    >>"SlyckTom" <tom@slyck.com> wrote in message
    >>news:vim5d293sspm1m2lbm6cnnl4v56af2b0vq@4ax.com. ..
    >>> Hi All,
    >>>
    >>> I have a 1993, Corolla, 4 cyl, 1.8 liter, EFI engine. The car has
    >>> 200,500 miles.
    >>>
    >>> Here's the situation.
    >>>
    >>> When I'm driving at all lower speeds and RPMs, the tranny shifts very
    >>> smooth - as if it were new. However, if I'm entering an on ramp or
    >>> otherwise bringing the engine to high speed or high RPM (maybe
    >>> accellerating past 50 or 60)s, the tranny shifts into gear not as
    >>> smooth. I dont want to say it clunks or it shifts hard, because those
    >>> are too strong of words. It just isn't as smooth as during lower RPMs
    >>> and speed.
    >>>
    >>> After the tranny shifts down in this instance its smooth afterwards
    >>> regardless of speed or RPM...
    >>>
    >>> Does anyone have insight into this?
    >>>
    >>> TIA!!
    >>>
    >>>
    >>> Tom
    >>>

    >>
    >>You did not mention whether you have an automatic or a manual
    >>transmission,
    >>but since you are implying that it is an automatic, I'll give my 2 cents
    >>assuming that it is an automatic.
    >>
    >>What is the condition of the automatic transmission fluid (ATF)? Is it
    >>red,
    >>brown, or black? What it the level of the ATF?
    >>
    >>Assuming that the ATF level and condition are satisfactory, my guess is
    >>that
    >>the accumulators are worn. Automatic transmissions have a pump that is
    >>turned by the input shaft, and as engine RPM increases, pump output
    >>pressure
    >>increases. At higher RPM, shifts will be harsher due to the higher
    >>pressure, and accumulators act as a shock absorber to reduce shift shock,
    >>kind of like slipping the clutch a little on a manual transmission instead
    >>of popping the clutch.
    >>
    >>The increased shift shock is not harmful, and is actually a little better
    >>in
    >>terms of internal friction surface wear but if you want to reduce the
    >>shift
    >>shock, a competent technician should be able to change the accumulator
    >>without too much trouble, as long as there is good access to the
    >>transmission pan and valve body.

    >




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