Th400 trans cooler question ?
 

Looking to add a tranny cooler to my 67 gto...Question...do I run only the cooler and by pass the radiator cooler.....or run them together ? Thanks for any input

Being in N.H., I'd run it to the auxiliary cooler first, then through the rad cooler to avoid over cooling it.

LoL......I don't drive it in the Wintah....

Just my thoughts, no hard facts, IF the radiator provided enough cooling and no aux cooler was used
then you have that exit temp.
IF you then took that same exit line from the radiator and ran it thru an aux cooler, there is no way
that fluid could increase in temp, it has to go down in temp.

If you reverse that scenario, I see potential for the aux cooler to reduce fluid temp, and for the radiator (on a hot day)
to increase the fluid temp thus negating the gains the aux cooler made.

Only way to know is for someone with a temp gun to take temp readings.

Just my unproven 2 cents.

Most auxiliary trans cooler manufacturers recommend out of trans into radiator cooler then through auxiliary cooler then back to trans. That's how I have run mine with no issues. FWIW.

Correct. And recommended.

Have to understand that there is an X amount of temp drop from a cooler, and the radiator, same thing, when it comes to adding heat. For example, if the radiator drops the (ambient) temps by 40 degrees, it will do so if the water in the radiator is 160 or 220 degrees.

You control the drop amount by the size of the cooler.

Just like an engine, the trans has optimum operating temps. So it is possible to overcool.

Agree, In the Op's post he mentioned that he does not drive the vehicle in the winter.

Having a second cooler in line would mean that the trans fluid would take even longer to heat up with winter driving.

Summer only driving says that if the trans cooler in the radiator is sized properly then the trans temp will be in the normal operating range for most of the vehicle operation cycles.

Unless you actually know what the trans outlet temp is vs the ambient temp, you do not know if you will be in a fluid over-temp situation. Over-cooling can cause issues as well as lack of cooling.

To really give proper advice we need that last bit of info. Trans Mods and trans outlet temp to the radiator.

Tom V.

winter or summer driving, trans cooler & transmission companies suggest running through the radiator cooler first then out to aux cooler then back to trans.

if you dont have severe overheating issues, the rad cooler removes quite a bit of heat from the trans (or ads heat to get trans to operating temps) then the aux cooler removes more heat to get it to a comfortable temp range. i have always hooked mine up that way on street/strip cars & towing vehicles. a trans temp gauge is always good to verify temps but installing the cooler how they are intended will usually be best for most vehicles.

That drawing does NOT make any sense!

if youre refering to the 1st diagram i posted youre right, the arrows were messed up... these direction arrows for fluid flow are correct.

I run my line from the tranny into the rad, then a short hard line bent to the front to the in of the tranny cooler then the outline from the tranny cooler to the tranny.. I did a check with my heat gun on a hot day and what comes out is cooler then what goes in so that makes me feel good for the ole Goat.

It depends. Usually I just run it as a stand alone unit.

depends on what?

if you just do it as stand alone, you arent getting the full benefit of both coolers, especially with street driving, the aux cooler only works when there is good air flow, sitting still in traffic or low speeds gives you zero cooling & likely heating the trans more than needed compared with both the radiator & aux coolers. as well as no rad cooler wont get the temps up high or fast enough in colder climates.

Depends on if the radiator I have has provisions for a factory cooler.

I understand that coolers only really function if their is airflow, but how is that any different from a factory cooler? I would imagine sitting in traffic with a factory cooler isn't any different from a large external.

ok, was just curious what "it depends" was... unless you get a universal radiator or one from/for a 4spd car, replacements will have trans cooler provisions. running to the rad then to aux is how they work best & just a better way to cool an automatic trans IMO.

a factory rad cooler is submerged in water all the time, so while a radiator needs airflow too, its much bigger & takes a lot longer for the engine to overheat sitting at a light or in slow city traffic but still keeps the trans temp cooler than relying on only an aux cooler that is much smaller & just cant remove the heat enough unless your doing 30+mph for a sustained period.

I think of an aux cooler being like one of those old school steam heaters used in homes.
Steam goes in, it gets hot , then radiates heat. No fan.
Fan would be better, but unless a tran cooler is located near the exhaust parts
which are hotter than the fluid . . . . . .can't help but loose some heat.

Well.....when I take off out of the driveway and manually shift from 1st to 2nd it chirps the tires....and will chirp the tires for a while.....but when it gets run for 20 highway miles or so.....the tranny shifts good...but not that chirp of the tires.( which I like ). The car has the orig 4 core Harrison ...but it has a more efficient new core....and it stays at or under 200 degrees.... I was thinking the trans cooler would keep me chirping the tire any time I want to.....

I do trans outlet to aux cooler, then to radiator, then back to trans. My cooling system keeps the engine at 180, so I won't be very far from that heat sink/source temp. If it is a cold day, I theorize that my radiator temp will add some heat back to the trans fluid to keep it from getting too cold. And if it is a hot day, my aux cooler does most of the pre-work, allowing the radiator to further cool it so it isn't much more than 180.

I have no IR gun data to share, but that is how I have run them for years with no ill effect.

So on a 1967 th 400...... which line is the out line to the rad....and which one is the return line...?

What fluid are you using?

As far as which cooler first? I would look at a chevy truck because they have both, and the auxiliary is mounted in front of the radiator. So, it does get air flow all the time. Either idling with fan draw or flow through at speed.