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tranny cooler install question
Posted: Wed Dec 18, 2002 6:24 pm
by IggDawg
Hey all. I'll be tossing in a tranny cooler for my 4EAT today or tomorrow. I've found the lines for the radiator section of the present tranny cooling system. My question is: Which of hte 2 lines, top or bottom, is the line to the radiator and which one coems from the radiator? I need to tap the right one or the cooler is useless. I need to tap the line from teh radiator for the cooler, and to the radiator for the temp gauge.
-IggDawg
Posted: Wed Dec 18, 2002 9:47 pm
by ciper
How would to cooler be useless? Contrary to what most say I beleive the cooler should be FIRST and the radiator second, in order to warm the fluid back up. I ran mine in in parralel to each other to reduce restriction.
Posted: Thu Dec 19, 2002 5:47 am
by IggDawg
I see what you mean. Use the new cooler to to cool the really hot stuf to less hot, and have the radiator either warm or further cool the fluid to optimal temperature? makes sense. and that would eliminate the whole "not getting up to temperature for f'n ever on cold days" problem. I've driven 50 miles in the Impreza before it gets above 140. AND EVEN THEN I have to do a few light powerbrakes to get it up do proper temp. then I have to drive around for a while to make sure it gets any moisture out of the system. :rolleyes: .
The only thing is that ideally the cooler is useful for getting very hot temps down. Like in a rallycross where I'm in first and very high revs the whole time.
-IggDawg
Re: tranny cooler install question
Posted: Thu Dec 19, 2002 6:52 am
by whitemr2
IggDawg wrote:My question is: Which of hte 2 lines, top or bottom, is the line to the radiator and which one coems from the radiator?
I just had an external tranny cooler installed by a shop specializing in auto trannies. They hooked it up in series with the radiator cooler, with the bottom radiator cooler connection being the one to go back to the tranny.
Now granted, they could have hooked it up wrong, but it seems like the right way to me...
Posted: Thu Dec 19, 2002 2:07 pm
by IggDawg
Ok. That's kinda what I figured. I did a light brakestand without launching to spike the heat a little. I ran out and touched both hoses to see which one felt much hotter than the other and it was the top one. so I assumed that was the one coming from the tranny, which would concur with what you're saying. I think the default, at least, is to hook it up after the radiator.
I installed my tranny temp gauge last night too. I had some extra hose on the tee that I coiled up. I hooked up the temp gauge inline with the top radiator line, assuming that was the rline coming from teh tranny. So to double check the flow direction, I pinched the hose real tight, and felt pressure on the transmission's side of the pinch. so that would suggest the flow was in fact coming from the tranny and in the direction of the radiator.
All this is much better than my last try at flow direction. "Ok, Seth... I have the lines unhooked here. Turn the car on for a second and we'll see which way it flows..." :rolleyes: . I bet you can figure what came next

. tranny fluid everywhere.
Posted: Thu Dec 19, 2002 10:27 pm
by whitemr2
I found this image on AllData for the Subaru Legacy:

Posted: Thu Dec 19, 2002 11:26 pm
by ciper
BTW guys, that filter kit (with a filter) costs maybe 15$ while just a replacement filter is 60$!!!!
I replaced my filter and bought the whole kit. You get extra brand new subaru bolts as a bonus

Posted: Thu Feb 20, 2003 8:15 am
by mikec
How often should that filter be replaced? And how hard is it really? I'm going to go out on a limb here and guess that the filter on mine has never been replaced (only owned it for a month now, so I'm trying to fix previous mistakes).
How about installing a temp gauge. Is that line a good choice for the sender?
So many questions!

Thanks in advance everyone.
Posted: Thu Feb 20, 2003 8:33 am
by eastbaysubaru
Couple other questions...
1) What's the part number for the filter kit?
2) Is the Tranny Cooler a Subaru part or did you get an aftermarket kit?
A. If it is a Subaru part, do you have a part number?
Thanks in advance guys.
-Brian
Posted: Thu Feb 20, 2003 3:03 pm
by Legacy777
I've been told you don't need to replace the filter......I don't think it would hurt anything. I did mine around 140k miles.
Cooler is probably an aftermarket setup.
I had the part number for the filter kit, but I think they changed it....ciper may have it.
Posted: Thu Feb 20, 2003 10:53 pm
by IggDawg
the line going from the tranny to the cooler on the side of the radiator is a perfect place for it. I believe it's the top line. that's where I have mine. that way you get the temp of the fluid as it's just leaving the tranny.
Posted: Thu Feb 20, 2003 11:36 pm
by mikec
Installing a temp gauge must be a pretty messy proposition. Or would clamping the hose work? Never mind, I think I just answered my own question.
Where did you get yours from IggDawg? My first thought would be AutoMeter.
Posted: Fri Feb 21, 2003 2:49 pm
by IggDawg
Even better! SunPro. at my local Auto Zone. They sell decent looking water temp gauges for like 15 bucks. it's just marked "temp". not "water temp." so it's not jimmy-funding it too much. the temp range is about right for the tranny. It goes from 100-280. 170-180 is standard operating temp for a 4EAT, and 200 is getting up there. 220-240, you should really stop what your'e doing. mroe than that and you REALLY should stop what you're doing. the temp range is just about perfect. It's not that messy. and you can mount it under the dash where that little compartment is to the left of the steering wheel. you can see it through the spokes of the steering wheel. temp doesn't change all that fast, so it's not something you need to glance at every second. I've found that to be a goo dplace for it.
Oh, and SunPro is made by Snap-On IIRC, so it's actually quality stuff. they sell AF gauges for 20 bucks now. same stuff as auto-meter. jsut cheaper.
Posted: Fri Feb 21, 2003 4:06 pm
by mikec
so it's not jimmy-funding it too much

I've gotta remember that one!
As for the sender itself, how exactly did you install it? I read the install instructions for the Sunpro one, and it said you couldn't use a tee fitting to install it. How else would you install it inline with the flow to the radiator? Or are they talking about the situation for oil where you want both a pressure and temperature sensor coming from the same hole?
Now I just need some money to buy the gauge!

Posted: Fri Feb 21, 2003 4:13 pm
by IggDawg
yeah, you can use a tee. go to home depot and get a brass tee and a pair of barbed fittings you can screw into it. don't forget to get teh yellow flavored petrol compatable teflon tape! the sender should dip into the tee far enough to be felt by the flow without reducing it significantly. about 1/2 cm IIRC. only the tip needs flow. thermodynamics will do the rest for you.
Posted: Fri Feb 21, 2003 4:17 pm
by mikec
Ah yes... Thermodynamics.... It's amazing what you forget when you've been out of school for a year and half.
Thanks!!
Posted: Tue Jan 22, 2008 3:15 am
by skid542
Bringing an old thread back from the dead...
I've got my AC condensor out and have plenty of room for a cooler. So far the tranny is holding up fine, but with an exhaust, TMIC, and a little bit more boost I'm a bit concerned.
So the question is, has anyone been able to confirm the fluid flow direction? I want to put my new cooler before the radiator so I have a 'thermal stabilizer' if you will.
Also, I've heard lots of people say they've installed coolers, but there is ZERO discussion about the size of the cooler. Any info there?
Thanks for the help guys.
Posted: Tue Jan 22, 2008 7:17 pm
by Legacy777
I could have sworn I had a picture or seen a diagram that showed the direction....but I can't find it.
I think there was someone that may have tested this.....but it was from a long time ago.
Posted: Wed Jan 23, 2008 3:30 am
by skid542
I've been doing a lot of reading over on Nabisco about this subject and came across a thread about this started by IggDawg himself -
http://forums.nasioc.com/forums/showthr ... ion+cooler .
There is a fair bit of information about sizing and sources in that thread.
For anyone that comes across this thread in the future, if you search for "transmission + cooler" you will find a ton of information that isn't available here.
I will be buying a cooler this week and installing shortly. I will create a write up when I do such.
Posted: Wed Jan 23, 2008 3:57 am
by internetautomart
I need to find a thermostaticly controlled cooler. my fluid doesn't get warm enough quickly enough these days
