66 Newport hard shifting when hot

Engine, Transmission & Driveline

  1. surfdad1060

    surfdad1060 New Member

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    I have a 66 Newport with a fresh 440, now that summer has really hit hear in SoCal the trans has started to shift hard when it gets hot. I’m wondering if my cooler lines are clogged or maybe I need an auxiliary trans cooler. Anyone have any ideas?
     
  2. Snotty

    Snotty Senior Member FCBO Gold Member

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    How is the fluid level? If it's low it will shift hard.
     
  3. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    Checked in neutral, warm with motor running.
     
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  4. Ripinator

    Ripinator Senior Member

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    Here we go again. . .
     
  5. Big_John

    Big_John Illegitimi non carborundum FCBO Gold Member

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    Do I have to take a picture of what it says on the dipstick? :rofl:
     
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  6. surfdad1060

    surfdad1060 New Member

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    Fluid is full
     
  7. Snotty

    Snotty Senior Member FCBO Gold Member

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    Very well. Is it the right grade? I have lived in Bakersfield, where the temps get into the 110s, and now in Chico where 106 is not uncommon, and I have never experienced what you are. The temperature should not change the shifting of your trans. But, if you're running the wrong ATF, it might just thin out at higher temps.