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Let’s talk transmission temps

Discussion in 'Engine & Drivetrain' started by BH1989, Mar 8, 2021.

  1. Geotrash

    Geotrash Supporting Member

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    Yup. Factory thermostat opens up as 195, so when I'm not towing, that's where she sits all day long. Towing is another story. And towing uphill in hot weather is yet another story that involves an extra transmission cooler and bigger radiator. :)
     
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  2. 03_GMC

    03_GMC Full Access Member

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    Dude seriously get a tune! I know the bigger Ext trans cooler is a must but the new fan settings are amazing so far with the tune!!


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  3. Foggy

    Foggy Full Access Member

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    Unfortunately, Even With a Tune... Highway towing temps won't be affected.
    The fans don't (and won't and shouldn't) operate above a certain MPH..about 40 mph

    So when towing at highway speeds, the fan settings don't mean a thing at all

    Thats' the reason why many of us that tow have explored better cooling options
    such as better radiators and external trans coolers.

    Yes, around town, having the fans set in conjunction with a lower thermostat
    temp will help... but not on the highway
     
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  4. Geotrash

    Geotrash Supporting Member

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    Where did you mount your Derale?
     
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  5. Foggy

    Foggy Full Access Member

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    I have it mounted behind the bumper. I took out the oem aux cooler and
    plumbed the derale in...
    the oem cooler was right behind the intercooler, so I figured it was getting
    a lot of heat from that
    I still have the front apart due to installing my Snow Perf Meth Injection kit

    I'll see if I can get some pics of it in the next day or two. I mounted the top of
    it directly to the bumper bar itself. I'm going to run some small hardware
    thru the license plate holes to support the lower part of it
    And just putting the fan on toggle switch. It came with a thermostat, but
    I want to have complete control... I'm ocd that way
     
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  6. Geotrash

    Geotrash Supporting Member

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    Photos would be
    Photos would be amazing! And I'm OCD, too. :)
     
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  7. 03_GMC

    03_GMC Full Access Member

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    Changing the fan duty cycle settings in the ECM does help at highway speeds. It actually helps at all speeds. They aren’t dependent upon speed but actually on the temperature of the coolant. It sounds to me like you have a diesel swap in your truck which is a completely different ball game to what we are talking about. I agree that upgrading the tranny cooler is a must but it still shouldn’t be the only thing that is done. Like I stated earlier in this thread the factory programming for the fan duty cycles is crap and doesn’t move a lot of air until it starts getting harder to cool the engine and trans down. So again yes it will help at highway speeds. This isn’t a clutch fan setup, it is electric cooling fans.


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  8. Axm1096

    Axm1096 Member

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    Im sorry i dont mean to steal the thread but i feel like theres a alot of support on this one can any one tell me why i have this leak and what gasket i need to repair it thank you in advance

    20210412_171441.jpg
     
  9. Foggy

    Foggy Full Access Member

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    I really really really don't like to argue with anyone on the internet.. I'm too old...
    But I want people to know the facts>>>>>
    Your electric engine cooling fans will NOT be commanded to turn on NO MATTER what
    the coolant temp is at highway speeds...
    Maybe you have a custom tune that does command them to ON at 60mph,
    but it really wouldn't have any benefit due to the incoming air at speed anyway.
    This is the reason the OEMS do not do it.
    IF yours turn on at 60mph, then you have the unicorn... I do understand the differences in mechanical, electrical, viscous types of fans that the oems have used
    for over 100 years

    I do not have any "swap" crap in my rig. It's the factory engine, trans, diffs, etc/
    I do have a supercharger and a tune of course.
    My fans are programmed to come on low speed at 202* and high speed at 212* ..
    I can watch my duty % at all times so I know exactly when the fans operate.
    But as stated, oem electric fans don't come on at 60mph..Now, if you slow down then
    they do come on and will run on high if temp demands it. But keeping cool at a steady
    60-70 mph while towing on grades in 90*+ weather presents a whole different set
    of parameters
     
    Last edited: Apr 12, 2021
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  10. Geotrash

    Geotrash Supporting Member

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    This is the part that concerns me and I want to be ready for *before* I run into trouble on a trip. Thanks for the input - very helpful.
     

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