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Trans cooler - Bypass or run inline with radiator

Discussion in 'General' started by someguy360, Nov 24, 2017.

Trans cooler setup

  1. Bypassed (Direct from trans to cooler)

    6 vote(s)
    75.0%
  2. Inline (run through both the cooler and the radiator)

    2 vote(s)
    25.0%
  1. someguy360

    someguy360 Well-Known Member

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    Hi Guys,

    Thought I'd put a quick poll up. Everyone seems to have different opinions on the matter.

    What does everyone recommend for a trans cooler, bypass the radiator completely to avoid milkshaking the trans.

    Or keep it running inline with the radiator.

    I'm upgrading mine to a beefier PWR cooler getting ready for summer and would like to bypass the radiator as I've seen what can happen when the internal tanks let go. But am unsure if this will keep the trans cool enough in 40+ degree SA weather (I'm running a stock 4L60E, which a few km behind it).

    Thanks all
     
  2. EYY

    EYY Well-Known Member

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    If you're able to spend a bit more on a large auxiliary cooler and have the room to mount one separately you're better off doing that. I've done it both ways. Seems pretty rare for the radiators to split between oil/coolant anyway. Currently I'm running the factory cooler along with an additional cooler.
     
  3. stockies

    stockies Bannana

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    On my VN I had it set up bypassed as the gearbox was replaced with a second hand "no warranty" one because I was in a hurry.

    Saw it the other day, (Mechanics son owns it now) still rocking the same set up, right down to the" suspect" gearbox.
    I trust the factory radiator cooling setup in the 2gens about as much as I can throw the entire car one handed.

    I mounted my trans cooler so it was visible through the grill for both maximum coolness of the car and gearbox.
     
  4. VT&VX

    VT&VX Active Member

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    If you want to cool your Auto Transmission on a 40 degree day, your choices would be running the transmission fluid through a separate air cooled radiator which is in 40 degree air or run the transmission fluid through the inbuilt radiator tanks which are 100 degrees. Hmmmn, which one to choose?

    Well if you bypass the radiator you will have two pairs of connections so you could do two transmission coolers. If you have decided to segregate then you can get a PWR for manual car and you will have more volume of coolant in the radiator for the engine (because those oil cooler tanks have to take up some volume space in there.

    You can get thermo fans for your twin oil coolers.

    The cops will check your car looking for the turbos because two big oilcoolers up front will look like twin SICs o_Oo_O
     
  5. stockies

    stockies Bannana

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    Crappy pics, but it was all I could find
     

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  6. VT&VX

    VT&VX Active Member

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    Not sure why you posted pics of your car? Unless you want to show the limited front ventilation because driving lights?

    You could run a couple of these
    [​IMG]

    since they are black, less noticeable and won't be mistaken for intercoolers by cops.

    Might be a good idea to screen the front of these with stainless steel mesh to protect from stone chips.
     
  7. EYY

    EYY Well-Known Member

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    What are you talking about? Stockies posted pics so that you can see where he mounted the cooler. Those lights won't hinder air flow at all and aren't inline with the radiator anyway.

    Can't see any reason you'd be pulled up for having a transmission cooler, regardless of the colour.

    You don't need to run multiple coolers, just run one that's adequately sized.
     
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  8. stockies

    stockies Bannana

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    Calm down, was only to show a mounting option.
    And if you think a set of driving lights will block ventilation, your need your head examined
     
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  9. Tonner Matt

    Tonner Matt Well-Known Member

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    My 2 cents worth........
    Bypass the radiator and go straight to the cooler
     
  10. Not_An_Abba_Fan

    Not_An_Abba_Fan Exhaust Guru

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    Bypass the radiator. Your radiator temperature can run between 90 and 105 degrees consistently, the trans temp can range about the same, but unlike an engine, the cooler it runs, the better it is for it. And engine is more efficient when it's hot, a trans isn't.
     
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  11. immortality

    immortality Can't live without smoky bacon! Staff Member

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    Not that I disagree about engine/coolant/trans fluid temps but isn't the internal trans cooler in the radiator on the cool side? if so then it won't be in that 90-104°C temp range which you would see on the radiator inlet/hot side.

    So if you were to run it as per the factory, trans > radiator cooler > external cooler > trans you get 2 goes at cooling the fluid.
     
  12. harrop.senator

    harrop.senator Well-Known Member

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    The best way to do it in theory is on the return line. The radiator helps the Trans oil get up to temp and then the aftermarket cools it further.

    This way the Trans temp runs cooler then factory but it's within a good usable range and not too cold. Personally don't know how colds to cold think it was under a 100 faranheit its been awhile since I've read into them.

    Then theirs the if the tank splits it contaminates theory. It does , obviously . But as said theirs not all that many commodores with mixing issues due to the radiators internal cooler. The ba bf Falcons are shocking for it though and a lot of aftermarket companies have the issue not just oem and if they can bypass in those may bypass in a holden one can't be that bigger design difference between them.

    Honestly mate ask ten people get twelve different answers you'll have to make your own mind up.
     
  13. VS 5.0

    VS 5.0 Well-Known Member

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    In my experience, the factory set up worked fine for the 292,xxx kms the car did till I sold it.

    Hot weather, peak hour traffic etc. Never got the milkshake.
     
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  14. mpower

    mpower Well-Known Member

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    I've considered one of these things but can't find any evidence that it is of any benefit whatsoever to a daily driver/road car otherwise I'd buy a couple. My understanding is cars towing MAY benefit but once again - nothing out there to prove it afaik.
     
  15. uniacidz

    uniacidz Harden the Frak Up

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    Mine is from transmission to radiator to transmission cooler factory back to transmission

    Never had need for dedicated cooler
     
    Last edited: Nov 24, 2017
  16. ozNick

    ozNick Active Member

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    Yes, you are correct for normal driving. I assume that is what the OP is doing and the 4L60E is a pretty sturdy unit.

    But under stress (e.g. pulling a boat up a hill at 40 degrees) the whole system starts to heat up, quickly. The cool side of the radiator is not as cool as you would like it. Add to that the trans working hard, an you will have very hot trans fluid before it hits the now, not so cool side of the radiator.

    Agreed, best pass it through a dedicated trans cooler before returning it to the trans, whether you run it through the radiator or not if you need additional trans cooling especially if towing (or you have a 5L40E).
     
  17. immortality

    immortality Can't live without smoky bacon! Staff Member

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    I have the factory fitted external trans cooler as fitted as part of the towing pack and seems adequate unless you do a lot of spirited driving.

    I'm in nz so don't regularly see 40 degree air Temps.

    Stuff like this is also why I like to fit a coolet thermostat and lower thermofan on/off settings. Ours never gets over 90 degrees C even when towing.
     
  18. harrop.senator

    harrop.senator Well-Known Member

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    Put a Trans temp guage and you may see the need for it think it was immortality posted a picture the other day about the mileage expectations and the difference in life span at regular different heat ranges.
     
  19. NeddyBear

    NeddyBear Veteran Mountain Biker

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    We bypassed the radiator and yes a tad costly but compared to a new transmission great value for money.
     

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    Last edited: Nov 29, 2017
  20. immortality

    immortality Can't live without smoky bacon! Staff Member

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    I had a temp gauge on our old VS, now I'll admit the trans was stuffed and was probably running a little warmer than normal but I saw some huge temps. One day, middle of summer climbing out of Piha beach behind a huge truck doing about 20-25km/h going up the slow windy road, temps well in excess of 200°F but as soon as I managed to pass him and get some airflow through the front it came right back down. Interestingly the most odd time I ever saw excessive trans temps was one day stuck in traffic, it was winter so didn't have the aircon on. Engine temps did their usual thing going up and down as the thermofan cycled on/off but the trans temps slowly climbed and were again heading north of 200°F. To solve that I turned on the aircon which keeps the thermofan running and the trans temps slowly dropped.
     
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