Transmission Cooler ...which Way To Connect ?

Submitted: Saturday, Jan 31, 2015 at 15:11
ThreadID: 110926 Views:1825 Replies:5 FollowUps:5
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Hi guys

Ive recently got myself a new (well near new 30k on the clock) dual cab and it has a 6 speed auto transmission.

Ive bought myself a auxillary transmission cooler kit to help keep things cool in the trany dept.

I want to run it in series with the existing transmission cooler which is part of the radiator (EG make use of new auxillary tran cooler AND main radiator)


should i run the new auxillary auto transmission cooler in circuit before the radiator or after ?

My thought would be to cool the trany fluid down BEFORE it goes through the radiator to assist also with the reduction of heat going into the engines coolant and to also keep the motor coolant cooler.

BUT the instruction with the kit say for a series connection to install the auxillary tranny cooler AFTER the radiator..may be their way of thining is to remove as much heat with the radiator coolant so the transmission fluid it can be as cool as possible before returning to the transmission.

any thoughts

Many thanks in advance

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Reply By: rowdy - Saturday, Jan 31, 2015 at 16:07

Saturday, Jan 31, 2015 at 16:07
I've done them both ways but usually as per your instructions. I've only put them before the radiator if there's been a problem with engine temp getting high.

Cheers Graham
AnswerID: 545118

Reply By: pop2jocem - Saturday, Jan 31, 2015 at 16:36

Saturday, Jan 31, 2015 at 16:36
As you have stated John. Between the transmission outlet and the radiator cooler inlet, i.e. before the radiator.

Advantages of removing excess heat that may impact on the radiator's ability to control the engine coolant temperature's in high ambients when towing and also to allow some heat to be re-introduced to the transmission fluid if operating in extreme cold.
Although I can't think of an area in Australia where that may be strictly required.

I guess let's go back to the basic idea of installing an auxiliary cooler in the first place.
The removal of excess heat that may be beyond the ability of the whole vehicle's cooling system to handle in extreme conditions. What's the point of removing any heat after the engine cooling system has possibly been over worked.

AnswerID: 545120

Reply By: futch - Saturday, Jan 31, 2015 at 17:45

Saturday, Jan 31, 2015 at 17:45
Do your self a favour & bypass radiator altogether
AnswerID: 545126

Follow Up By: TomH - Saturday, Jan 31, 2015 at 18:24

Saturday, Jan 31, 2015 at 18:24
I second that A fair few years ago there was a lot of Toyota cars that had the trans cooler in the radiator.

Lots ended up with water in the tranny due to the joint fracturing where the pipe entered the radiator.

The solution was to use a short pipe between the two joints to blank them off and completely bypass the radiator.

No more troubles except for the Dumb ass who replaced the auto and didnt do the fix. Cost him another box a week later.
FollowupID: 832656

Reply By: Member - Fab72 (Paradise SA) - Sunday, Feb 01, 2015 at 09:11

Sunday, Feb 01, 2015 at 09:11
G'day John,
One thing to consider here despite the opinion of others is warranty.
If your bus is only 30K old, there's a good chance it's still under a manufacturer's warranty. Also the cooler manufacturer has given an instruction on how to fit the cooler.
My 2 cents worth....forget the opinions of others and do as suggested by either the OEM of the vehicle or the supplier of the cooler kit.
Cover your backside mate.
AnswerID: 545150

Follow Up By: Member - DOZER - Sunday, Feb 01, 2015 at 19:20

Sunday, Feb 01, 2015 at 19:20
Im hearing 2 possible questions, i agree the tranny cooler should be fitted pre radiator, as the cooler oil will put less load on the cooling system, it also should be physically installed up front of the radiator aswell. Lastly, also agree that water from rad, if it is allowed to get into an auto, will kill it quick, so bypassing the rad is a good idea, thing you may not know is the water actually heats the oil when cold, bringing the system up to temp quicker, but my guess is this is more important in alpine areas....
FollowupID: 832715

Reply By: Sacred Cow - Monday, Feb 02, 2015 at 07:49

Monday, Feb 02, 2015 at 07:49
If you instal the cooler before the radiator cooler, you will re-heat the ATF to the temperature of the radiator which will be +85 degrees when it passes through the radiator. You want the ATF at the lowest temperature possible so put the external cooler after the radiator as per the instructions.

AnswerID: 545206

Follow Up By: Albany Nomads - Monday, Feb 02, 2015 at 09:04

Monday, Feb 02, 2015 at 09:04
Thanks glen
After a bit of consideration, you and the manufacturer are correct.
The aim is to get the transmission fluid as cooll as possible ... And with cooler transmission fluid flowing through the system in return gives you cooler trany fluid passing through the radiator ,
Hanks all for your feedback
FollowupID: 832739

Follow Up By: Member - DOZER - Monday, Feb 02, 2015 at 15:16

Monday, Feb 02, 2015 at 15:16
Glenn, splitting hairs here, but the cooler is in the cold section of the rad, meaning its probably seeing 40 deg after the water cools before being sucked in to the motor to be reheated...i own a fairlane, and have bypassed the rad because they always leak water into the tranny and kill the auto. Fairlanes and most fords have an air cooler in the line aswell, it seems to be doing the job by itself famously.
I dont think you can go wrong adding the air to air in a hot enviroment like australia, especially if you are towing.
FollowupID: 832766

Follow Up By: Member - DOZER - Monday, Feb 02, 2015 at 15:18

Monday, Feb 02, 2015 at 15:18
ps, ensure you top up the tranny, or alternately, get a ervice straight after installing cooler, as the oil it uses, may cause low level in the tranny. most newish trannies run synthetic to pay someone to do the service, that way, you get new filter, oil and gasket for $150ish.
FollowupID: 832767

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