External transmission fluid coolers .

[WyrTwister]

Is it better to connect the external cooler to the supply line or the return line ( at the radiator ) ?

One person told me , for winter , the supply line . If the fluid was cooled too much , by the external cooler ( assuming not towing ) the " radiator " cooler would warm the fluid back up ?

Thanks ,
Wyr
God bless

 

[tcp71]

Stock are generally after the radiator loop before heading back to the pan.

 

[Oro_O]

This is almost a religious argument so you will get answers on both sides.

Since you are in Texas, let's cut through the back and forth talk as well as certifiable [censored] and acknowledge you want maximum cooling. Put it downstream of the radiator - thus in the return line. Unless you are in that part of Texas that is always below 0F four months of the year. No? Then put it downstream of the radiator.

 

[4wd]

This - fluid cools better than air - fluid and air cooling combination is what you want ...
(I have installed several aftermarket coolers).

 

[Linctex]

Every cooler instructions will always say to place it in the line that returns back to the trans, not before the radiator cooler.

 

[BubbaFL]

I've bypassed the radiator cooler entirely on some vehicles, just to avoid having to replace lines or source custom fittings.

Depending on the vehicle, the transmission may have a bypass valve that prevents fluid from going out to the cooler until it warms up.

 

[jeepman3071]

Originally Posted By: tcp71
Stock are generally after the radiator loop before heading back to the pan.


This.

It doesn't make sense to send cooled fluid from the cooler back through the ~210*F radiator before heading back to the transmission.

My B&M external cooler is set up this way:

Transmission> magnefine filter> radiator heat exchanger > B&M plate cooler > back to transmission

The trans shifts great, and fluid stays bright pink even after 30k miles.

 

[plaguef]

These external coolers are not really needed, the design from when the car is built allows for cooling, so. Do what you like.

 

[Claud]

Originally Posted By: Linctex
Every cooler instructions will always say to place it in the line that returns back to the trans, not before the radiator cooler.


Every aftermarket cooler I have fitted had instructions to do plumb it in before the radiator cooler. But this is BITOG, so you will nearly always get conflicting advice...

Claud.

 

[HerrStig]

Originally Posted By: jeepman3071
Originally Posted By: tcp71
Stock are generally after the radiator loop before heading back to the pan.


This.

It doesn't make sense to send cooled fluid from the cooler back through the ~210*F radiator before heading back to the transmission.

My B&M external cooler is set up this way:

Transmission> magnefine filter> radiator heat exchanger > B&M plate cooler > back to transmission

The trans shifts great, and fluid stays bright pink even after 30k miles.

If the fluid is leaving the transmission at 210 or above, the radiator cooler will have less heat to dissipate if the external cooler drops the temp first.

 

[Ethan1]

Originally Posted By: plaguef
These external coolers are not really needed, the design from when the car is built allows for cooling, so. Do what you like.


There are transmission designs that have heat issues from the factory. How can you deny that?

 

[Claud]

Originally Posted By: jeepman3071
Originally Posted By: tcp71
Stock are generally after the radiator loop before heading back to the pan.


This.

It doesn't make sense to send cooled fluid from the cooler back through the ~210*F radiator before heading back to the transmission.

My B&M external cooler is set up this way:

Transmission> magnefine filter> radiator heat exchanger > B&M plate cooler > back to transmission

The trans shifts great, and fluid stays bright pink even after 30k miles.

If the coolant is at 210 on its way back to the engine you have a problem...

But if you are happy with your setup and the transmission works fine, don't fix what ain't broke...

Claud

 

[mightymousetech]

Originally Posted By: plaguef
These external coolers are not really needed, the design from when the car is built allows for cooling, so. Do what you like.


Maybe OP has installed a trailer hitch and now plans on towing? Almost every tow package I install on a new car comes with an additional trans cooler.

 

[HangFire]

Originally Posted By: plaguef
These external coolers are not really needed, the design from when the car is built allows for cooling, so. Do what you like.

How do you know it's a car?

Why do so many pickups and SUV's offer transmission coolers as part of the tow package? (For example, my Honda Pilot has the factory optional trans cooler, P/S cooler, and hitch receiver.)

 

[meep]

my stock oem 'yota cooler does the aux first, then the rad second. The trans also has a tstat that bypasses the whole shebang below 135F.

Radiator temps are always lower than engine temp until the cooling system is entirely maxed out and the t-stat opens 100%.

What we miss----- we should really be watching the rear end. The trans is actively cooled - the axle is not. In my tundra I have to flog it hard with a 4000+ tow (I've pulled up to 6k with it) on mountain grades to get the trans over 220F. But I can step out of the car and feel the heat radiating off the axle even after level terrain. It has nothing but its own surface area for removing heat.

-m

 

[plaguef]

Well. Was always of the belief that those coolers were largely unneeded, places like Aamco have you believe every transmission ever made, regardless of vehicle, needs one. And that's simply not true.

Now, if talking special application like towing ? Or a trans with a known shortcoming? Well, that could be different.

Make sure radiator fins are clean, as well.

 

[bullwinkle]

If you tow, or have a transmission that has poor circulation (causing ATF overheating), like the Ford E4ODs that we used to run in company vans that were infamous for burning fluid, an external cooler is a good idea. When it comes to ATF, IMO there's NO SUCH THING as too cold! Well, maybe in northern Canada or AK in winter, but a winter front would fix that.