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  • Dex VI in a 4L60E?

    From Woozy Song@suzyw0ng@outlook.com to rec.autos.tech on Mon Nov 17 17:47:14 2025
    From Newsgroup: rec.autos.tech

    I booked in automatic tranny flush and they said it should have Dex 6
    fluid. These dinosaur transmissions were specified for Dex 3. My other
    car with 4L60E lasted 300,000 miles.
    And I should mention that I trust this workshop. They are a bunch of
    guys who left a dealership when it got taken over. I always had good
    service from them before they started their own workshop.
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  • From kludge@kludge@panix.com (Scott Dorsey) to rec.autos.tech on Mon Nov 17 11:24:26 2025
    From Newsgroup: rec.autos.tech

    Woozy Song <suzyw0ng@outlook.com> wrote:
    I booked in automatic tranny flush and they said it should have Dex 6
    fluid. These dinosaur transmissions were specified for Dex 3. My other
    car with 4L60E lasted 300,000 miles.
    And I should mention that I trust this workshop. They are a bunch of
    guys who left a dealership when it got taken over. I always had good
    service from them before they started their own workshop.

    The newer ones will effectively replace the older ones but in this case compatibility is poor so you really do need to flush out all the old fluid
    and replace it all, you can't just mix the two.

    I am not a fan of doing a full flush unless it's being done on a regular
    basis, because the flush can dislodge junk and suddenly you start having problems that you weren't having before. If it's an older transmission
    that hasn't been getting fluid changes or flushes on a regular schedule
    in the past, I would much rather do a change than a flush.

    So... if you do a change, you will need to use Dexron III. If you do a
    flush, the Dexron VI will be a more stable product.

    Your call. It's your transmission and you know the history and we don't. --scott
    --
    "C'est un Nagra. C'est suisse, et tres, tres precis."
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  • From Xeno@xenolith@optusnet.com.au to rec.autos.tech on Mon Nov 17 21:45:54 2025
    From Newsgroup: rec.autos.tech

    Woozy Song <suzyw0ng@outlook.com> wrote:
    I booked in automatic tranny flush and they said it should have Dex 6
    fluid. These dinosaur transmissions were specified for Dex 3. My other
    car with 4L60E lasted 300,000 miles.
    And I should mention that I trust this workshop. They are a bunch of
    guys who left a dealership when it got taken over. I always had good
    service from them before they started their own workshop.

    The VI is a thinner fluid even though it is the current recommended. That
    may affect shift timing. If the trans has high mileage already, and it
    shifts ok, it might be best to keep it on III. See the other reply, valid points made.

    ____
    Xeno





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