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Trans cooler - Bypass or run inline with radiator

Trans cooler setup

  • Bypassed (Direct from trans to cooler)

    Votes: 7 77.8%
  • Inline (run through both the cooler and the radiator)

    Votes: 2 22.2%

  • Total voters
    9

immortality

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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.
 

harrop.senator

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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.
 

VS 5.0

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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.
 

mpower

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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.
 

uniacidz

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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:

ozNick

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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.
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.

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.
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).
 

immortality

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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.
 

harrop.senator

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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.

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.
 

NeddyBear

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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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immortality

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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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