Overheating towing with Denali 6.2L - Losing my F'n mind!!

Discussion in 'Engine & Drivetrain' started by rubicon1976, Jun 14, 2018.

  1. puckhead

    puckhead Full Access Member

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    I might be confused. Is there no coolant in the transmission cooler? Just transmission fluid? Or something different?

    Just did some quick research. Just so I have this correct, there are separate chambers in the radiator that cool different fluids?

    I guess I just flushed transmission oil? out of the the transmission cooler. Do I need to add some back in when I put it together? What do I use? Regular transmission fluid? Really deal like a newb right now!


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    Last edited: Jul 11, 2018
  2. swathdiver

    swathdiver Full Access Member

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    Yes, the radiator will have an internal transmission oil cooler and possibly an internal engine oil cooler. In the old days those coolers were in the tanks on either side of the radiator.

    Did you every sign up for AllDataDIY? They show you how to do it with the machine and with water.

    Yes, if you disconnected the lines and drained the fluid, you will want to add clean fluid back in and top it off at operating temperature.
     
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  3. puckhead

    puckhead Full Access Member

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    Okay, I will pick some of that up. Thanks a bunch, I could have had a mess on my hands. I will sign up for that all data diy asap.


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  4. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    For the record the "radiator" between the main radiator and the transmission cooler is the condenser for your A/C and NO you don't want to flush that... lol

    Also make sure you buy Dexron VI to top off the transmission fluid and make sure the transmission is up to operating temperature when you check the fluid level and that you are on level ground. It needs to be at the HOT mark on the stick.

    It is hard to tell from your photo but it looks like you may have an additional aux transmission cooler over on the drivers side or it could be an oil cooler but I can't tell where the rubber hoses connect.
     
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  5. puckhead

    puckhead Full Access Member

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    Thank you for the info! I appreciate it, this site is amazing, no clue how much this would have cost at the shop.

    Good thing I didn't drain the ac lololol.

    And yes, it is an aux transmission cooler. Had it installed a few years back.


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  6. swathdiver

    swathdiver Full Access Member

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    So you have three transmission coolers? One in the radiator, the KNP, and that aftermarket one too? You hauling park trailers across Death Valley?
     
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  7. kbuskill

    kbuskill ***CAUTION*** I do my own stunts!

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    I had the same thing before adding my aftermarket oil cooler...

    I needed room for the oil cooler and the 42" light bar behind the grille so I removed the factory aux trans cooler and kept my bigger aftermarket trans cooler.
     
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  8. 97audia4

    97audia4 Member

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    is the stock cooler even hooked up yet? Id like to see what lines they have routed into the cooler on the on the radiator.
     
  9. Jason_S

    Jason_S Full Access Member

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    Taking the garden hose and spraying all of those bugs out of your condenser would also help.

    FYI, I've seen a tailwind when driving cause a bit of a rise in engine and trans temps when going down the road loaded.
     
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  10. puckhead

    puckhead Full Access Member

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    I guess so! I would have never known. I took it to a shop a few years back because the truck was going into limp mode, usually after towing. They suggested an auxiliary tranny cooler. It either fixed it or it has been a band-aid now for 3 years I think.
     

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