When is it too late to change automatic transmission fluid?

Discussion in 'General Motoring' started by Dmitry of NJ, Nov 28, 2005.

  1. Dmitry of NJ

    Dmitry of NJ Guest

    I've heard that once you reach a certain mileage, it is better to keep
    the original transmission fluid instead of changing it.. Is this true?
    If so, when is it "too late" to change the auto transmission fluid?
    (in relation to what's best for the engine, not warranty)

    I ask because I recently changed the fluid for the first time on my
    78,000 mile Sonata (2000, V6). Before the change, the car was getting
    stuck in gear, not shifting well, and the crank sensor code came up
    during a scan. Now, it doesn't even start. I've ordered a new crank
    sensor and really hope that changing the tranny fluid didn't screw up
    the engine beyond the damage that was already there...

    ...Thanks you.
    Dmitry of NJ, Nov 28, 2005
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  2. Changing the transmission fluid cannot affect the engine. The problems
    are most likely unrelated, unless they're electrical. The engine and
    trainsmission are both computer controlled and could malfunction due to
    voltage irregularities and/or bad connections.
    Brian Nystrom, Nov 28, 2005
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  3. Dmitry of NJ

    Dmitry of NJ Guest

    Changing the transmission fluid cannot affect the engine. The problems
    Right. What I meant was: How does changing the transmission fluid at a
    late stage (in my case at nearly 80,000 mi) affect the transmission

    .... I've heard that doing this dislodges dirt and can be worse than
    keeping the original fluid, but would like to hear from people who have
    experience with engines and Hyundai's in particular.

    Sorry for the misstatement though- I understand what you're saying but
    it's a bit different than what I was thinking of in my post.

    Dmitry of NJ, Nov 28, 2005
  4. Dmitry of NJ

    hyundaitech Guest

    You never really know it was too late until you find out the hard way.
    Realistically speaking, though, you've only provided an acceleration to a
    trans failure which was going to happen anyway.
    hyundaitech, Nov 28, 2005
  5. Dmitry of NJ

    SAT.Dmitry Guest


    ...... so you're telling me the mechanic at my dealership had me
    "accelerate" a trans failure by advising a fluid change?

    I really, really hope that the reason my car isn't starting is the
    busted crank sensor.

    Hyundaitech- your post scares the crap out of me, and if you're right
    then I will go absolutely crazy on the guy who told my to do this, esp
    if a new trans is not covered by warranty.

    SAT.Dmitry, Nov 29, 2005
  6. Dmitry of NJ

    hyundaitech Guest

    Well, I think you're looking at it incorrectly. By your own admission, the
    transmission was already not operating properly. If your fluid was in poor
    condition, changing it could have very well have had the opposite effect of
    helping the situation. The real acceleration of trans failure came when
    the car was driven 78k without changing the fluid.
    hyundaitech, Nov 29, 2005
    alysoncottini, Nov 29, 2005
  8. Interesting (to me). My 1990 (bought new then) Excel GL with 110 thousand
    miles, still with the original transmission fluid (check levels but never
    added or replaced) operates perfectly. I wonder if it's because I let the
    dirt stay in there and don't disturb it. :O)

    -- Throttle Vamp
    Throttle Vamp, Dec 4, 2005
  9. Dmitry of NJ

    GP Guest

    GP, Dec 8, 2005
  10. Dmitry of NJ

    John Horner Guest

    Old wives tale. Keeping bad fluid in there is never a good thing.

    The tranny fluid certainly didn't hurt the engine. Something else is
    wrong, probably that sensor.

    John Horner, Dec 11, 2005
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