How to: Transmission Cooler Installation

[SBT]

I wouldn't add anything. Additives have a tendency to become "chunks" of stuff over time. Not good for valves, hydraulic servos or passageways in your transmission, lines or cooler. All it takes is for one small piece to jam something partially open or closed and things go south really quickly. YMMV, but plan accordingly

[Zephrant]

So the pdf shows it mounted behind the radiator, but I've seen other threads where it is mounted in front, which seems to make more sense.

 

Suggestions?

[SBT]

Z - Looking at the post # 234 pdf, the cooler is mounted ahead of the condensor/radiator...notice that the first step is to take off the grille. The only photos about behind the radiator are to show removal of the overflow tank and moving the fans assembly back in order to attach the plastic retain clips to the plastic straps holding everything on at the front. The thread you referenced had photos showing mounted to the front of the condi/radi

[Zephrant]

Ahh, I didn't read the PDF close enough. Thanks, that makes more sense.

[Zephrant]

Got mine put in last weekend, no issue at all. Thanks for the pdf and thanks to SBT for the help.

[Zephrant]

OK, got my pictures on the computer. I'll replace the white tie-wraps with black ones and paint the bolt heads some day.

 

I used a piece of rubber pond liner between the cooler and the brace, just for some padding and as a crush washer. I probably didn't need that brace on the top left, but I spent so much time cutting it to fit and painting it, that I decided to use it anyway.

[ClimberDHexMods]

Very nice!

[2.5GT_dude]

Any opinions about the Mishimoto universal trans cooler?

[Kodax]

Does the transmission cooler for 2.5l work for the 3.0R?

[2.5GT_dude]

^^^for the most part trans cooler are universal. It just having the right attachments for the lines and mounting.

[ClimberDHexMods]

In other words, yes.

[No DRFT]

I just purchased a Long Tru Cool LDP Cooler 4452. I took some pics of the size in comparison of a water bottle. This will go on the LGT soon.

 

http://img.photobucket.com/albums/v257/4A-FE/2005%20Subaru%20Legacy%20GT/IMG_3518-4.jpg

 

http://img.photobucket.com/albums/v257/4A-FE/2005%20Subaru%20Legacy%20GT/IMG_3525-5.jpg

[ported]

I had installed 8 years ago on our 2000 Outback a trans cooler. After getting trans oil change we loaded up the car, kids and camping gear, nothing towed and headed out. Over the Rockies into Alberta.

Arriving in Edmonton about 800 miles later I decided to get a proper trans flush. The shop owner called me over to smell the burnt tranny fluid. I had a cooler installed right there.

My point is that even without towing a trans cooler is needed and certainly doesn't hurt. I also had Royal Purple Max ATF put in. Shifting seemed crisper

[ClimberDHexMods]

I'll post this here since people are already subscribed to this thread:

 

I have a suspicion that the consensus on installing a transcooler for 2005-2009 5eat performance street driving and daily driving, is wrong.

There is so much hear-say and laughably illogical conclusions drawn about whether and how to install what trans cooler, it's disheartening.

 

First, let's be clear, there is very little reported data on trans temperatures in this forum. So without that, back to the basics:

 

1) Conveniently, we want ATF temp to mirror engine coolant temp.

2) ATF runs through the radiator.

3) ATF will warm up roughly along with coolant.

4) When warmed up, we want ATF to be slightly under coolant temp.

 

So most people are installing coolers After the radiator. Result? Don't know exactly. Presumably hotter ATF goes into the radiator, where temp is normalized by heat exchange. Given the speed of ATF Flow, it's probably not the most efficient heat exchange event, and the ATF thus probably comes out hotter than the coolant, though not as hot as when going in. So far so good. We're at the point where the engineers wanted us to be.

 

Now we start *&%^*& with it. Most put a cooler after the radiator. How well does that cooler work? Does it drop 10*F? 20? 30? Of course depends on input fluid temp, ambient air temp, air flow, radiant heat soak... the point is you have no flipping idea how well it works, unless you checked your temperatures with a computer or gauge (computer is better, using FreeSSM or RomRaider).

 

I think this aforementioned cooler solution is a lacking design.

 

Frank_ster and I have both been commenting that a bypass thermostat such as the Derale option is your best bet, added in before the cooler, so if the ATF is below 180*F, ATF won't go into it. I thought about this some more, and it's an improvement for helping the 5EAT warm up when cold, but then it's not much use. Remember, coolant is not going to be far south of 180* when warmed up. ATF coming from the trans will presumably be on the hotter side of 180*F since it can only shed heat by radiating it out of the transmission metal case, prior to hitting the radiator.

 

So, what to do? Well we want the ATF to be around 180*F, though 190-200* does not appear to be a problem, and appears to be normal for the 5EAT. What we don't want is ATF climbing well above 200*F.

 

Here are some solutions I've thought up. Obviously none are original or complex, but apparently they also aren't the "consensus".

 

1) Put cooler Before the radiator. Coolant will come out, then be cooled by the cooler, then be normalized by the radiator. Normalized is the key word. Moving fast, the ATF coming from cooler to radiator may be cooler than the coolant, so radiator can help warm it back up. If the opposite, in the city or similar, then cooler helps drop temps but not enough, then the radiator can help normalize ATF temp further downward to coolant temp. The key here is that NORMALIZATION of ATF temp gets to have the last say of ATF temp.

 

2) Same as #1, except add the bypass thermostat on the cooler. This will help again with warmup.

 

3) Change engine's thermostat to a 160*F unit. This will change the game entirely, don't want to go into it for now.

 

4) Just don't run a cooler at all. I like this option for street cars. Even if you make double of stock power, you're not making it all the time. You're barely using it at all. Instances of this solution not working are limited to a) road race track lapping, b) going up a long steep mountain, c) towing. Most people almost never do A or C. If you do frequently, look at other options.

 

5) Loop out the radiator ports. This is complicated, and for this I would at least recommend a bypass thermostat and a cooler. I do not know how well it work because I have not tested it. But I would like to know. TCI says to do this, so in their experience with American transmissions it must have worked well for them in their context. If you have a proper cooler and thermostat, only issues I can think of would be low speed overheating, and slower warmup time. I would like to know. Figuring the engine with the super hot combustion in it is a better source of warm-up heat than just the friction between moving parts inherent within the 5EAT.

 

Summary points:

-You're probably doing it wrong.

-You probably don't need to do it at all.

-Collect data and post your data in a comprehensive manor so we can learn something.

[BarManBean]

Damn you, Climber D. Keep quiet with your jargon and knowledge.

 

Seriously though, installing the transcooler BEFORE the radiator to allow for normalization makes a lot of sense--good call.

[seabass07]

I'll give my $.02.

 

I originally installed my cooler when I lived in S Florida. I was regularly seeing temps of 220F at the tc and 215F at the valve body while doing 3rd gear pulls. The aftermarket cooler after the radiator made a big difference and put my temps around 160 with normal driving. This was in 85F weather and stg 1. I didn't check much after that since the winters are non existent there.

 

Now that I've moved somewhere colder, I've been considering removing my cooler because I know I don't need it right now. I did some logging today and found that in normal to somewhat aggressive driving, my temps are between 120 and 130 max. So obviously, I am overcooling the transmission. This is at 45F ambient. So I think a thermostat would make a big difference.

 

Any thoughts on the thermostat constantly switching on and off from the extra cooler overcooling it? It seems that once it hits 180, it will send the fluid through the cooler which will quickly cool it down and close the thermostat. Any thoughts?

 

Another thing to consider if you are towing or tracking the car is that the overheating atf will heat up the coolant much faster if you put the cooler after the radiator, so in that situation, I can see it being better before the radiator. But for normal use, I'm not sure it matters much. I haven't tracked my car though, so I can't comment on that.

[ported]

Trans cooler before rad will cool the AT fluid and put less strain on engine cooling during hotter weather or towing. After the rad, the cooler will put more strain on the engine radiator possibly causing an overheat situation on the engine coolant?

During colder weather the AT cooler before the rad will benefit from engine heating.

I've just had a cooler installed on my 08 Outback and have noticed a couple of ticks lower on the dash coolant gauge. That was after a sustained run at 120kph for 20 minutes or more.

[seabass07]

After the rad, the cooler will put more strain on the engine radiator possibly causing an overheat situation on the engine coolant?

 

It will in extreme conditions, like towing over the limit up a mountain pass. I doubt it matters in reasonable conditions though. I didn't have a single problem with it except for that one condition, which most people won't deal with. I'm curious about whether it will happen on a track in hot weather though.

[ClimberDHexMods]

seabass07, your data validates my concerns and points, fortunately

What we need now is a year round set of data points with the cooler before the radiator.

With the series being cooler -> radiator, a thermostat interrupting the cooler would be less beneficial than when setup as radiator -> cooler. Still, it would be better than no thermostat. But weighing $65 shipped for the thermostat, and in the name of simplicity, my suspicion is that generally speaking for the modified masses the best bet is to go with modest-size cooler, and be fine without the thermostat. Or just don't buy a cooler.

I will look into the topic of ideal ATF temp. I keep hearing >200*F operating temps, the engineers must have known that's what it would be.

 

You have to weigh the driving you do. If you live with frigid winters and track the car in the summer, get a thermostat and a cooler big enough to keep your ATF temps stable on the track. Check whether you have the right size cooler via gauge or reading the data via laptop.

 

If you don't lap a race track or drive up mountains often, a small cooler is probably all you need, and thermostat for good measure if you like to do things "properly."

[ClimberDHexMods]

Also if you overcool ATF, and have a HexMods F1, you're probably going to have shifts be too firm, since the TCU likes to ramp up pressure when ATF is cold. I do not know the temperature scaling written in the TCU, and it would be a pain to find out.

[seabass07]

The 120-130 temps were with a small cooler. I saw temps over 200f without the cooler, but i doubt subaru engineers planned for several back to back 3rd gear pulls from 2k rpm. Thats a lot of heat from the torque converter that doesnt happen under normal conditions.

[ClimberDHexMods]

The 120-130 temps were with a small cooler. I saw temps over 200f without the cooler, but i doubt subaru engineers planned for several back to back 3rd gear pulls from 2k rpm. Thats a lot of heat from the torque converter that doesnt happen under normal conditions.

 

Can you flip the plumbing and re-log

[seabass07]

When im done with the 50 other things i have to do on my car.

[ClimberDHexMods]

When im done with the 50 other things i have to do on my car.

 

That's why I didn't volunteer myself

[BarManBean]

Climber: I'm going to install a trucool 4454 (i think) shortly. Want me to log anything prior to / after install for comparison? I like your idea of installing the cooler pre-radiator. If you're able to help me out as far as the direction of the ATF flow etc to plumb it this way that's how I'll do it. Should at least give data for pre/post cooler installation. Let me know!