Transmission cooler ?

[Eds84]

I just replaced my 700r4 in my 84 chevy 4x4 and would like to install a transmission cooler. I would like the fluid to go through the radiator and then to the new cooler. Which line do i connect it to ? :zoinks

[D&T Repair]

I have an 84 Chevy also, and mine is ran through the upper line.
Of course, this means that the fluid is ran through the trans cooler first, then through the radiator.

Why do you want the fluid to go through the radiator first?

[Mac_Muz]

Hmm the same could be asked , why would you want to run to air cooling then back to heated in the rad?


Since the rad cooler runs at 200 degrees or so, and the tranny runs at 350 degrees??? then heating oil to return it near to 200 seems odd to me. These are real questions... I do not mean to imply anything onee way or the other.

The lower line is into the rad hot from the tranny on my set up, then from the top rad to the air cooled cooler, and baack to the tranny...

Whether or not this is correct this is the way it is... Mac

[Eds84]

My thoughts were that the radiator would be hotter so send the fluid there than to the cooler. that would make the fluid cooler going back to the trans. unless i'm wrong ?

[Mac_Muz]

Well, Ed, In 87' I installed a cooler so it would send as cooled as possible atf back to the tranny, and still fried my tranny.

I have never heard of running a tranny to cold, or what can happen if some how a tranny is run to cold, and it has been -22 'F here a few days this winter and is -1 right now, and so is the tranny...

I am not in the habit of telling folks what to do, or telling some one his way is wrong if I really don't know, and I really don't know.

I have never heard of anyone testing out fluid temps and or incoming fluid temps, so I can't say what is best.

I do know I cooked my tranny in a single storm push here, on a long drive 1/4 mile maybe. That tranny worked and bam it didn't, and I got 700 dollars lighter for it...

i sure would like to hear the reasoning D&T has myself. Mac

[D&T Repair]

"The reasoning that D&T has"??
Dunno

Since the rad cooler runs at 200 degrees or so, and the tranny runs at 350 degrees??? then heating oil to return it near to 200 seems odd to me.

Let me figure this one out.

Your statement doesn't make much sense to me. According to your post, Trans fluid runs at 350 degrees, runs into trans cooler, to cool it down (from 350 down to LESS than 200??), then into radiator to heat it back up to 200 degrees........thats not right.
I only wish that my trans cooler lowered the temp that much.

The radiator cools the fluid, as well as the trans cooler. The order cannot make that much of a difference in my opinion, but like others have said, I don't really know for sure.
My setup works fine, and always has.
Never lost a transmission yet, and fluid was always the color it should be, with no burning.

Either way, who knows?
:)

David

[Mac_Muz]

D&T, let me say that first of all I have no specs with which to work from. Then allow me to rephrase the wording.

The auto tranny appears to run at apx 350 degrees, and so sends atf to the rad cooler. Since the rad cooler is part of the rad, and the rad is running around 200 degrees as that is about what the engine coolant is, the rad can not be cooler than that. So the ATF is cooled to something, but we don't know what. Certainly no colder than the radiator is.

I have no idea what the temp ATF retuning to the tranny might be using just a rad cooler, but it must be less than what it was when it left the tranny.

So if the rad cooler cools the atf and then you send it to an added on air cooled cooler, it will have to cause ATF to cool more, to a maximum amount depending on load, air speed and ambient air temps.

On the other hand sending atf to a add on cooler, and then back to the radiator the cooling effect can't be the same.

By doing this you limit what amount of cooling can be done, as you cool the atf and then probably reheat it some in the radiator.

What I am trying to eliminate is all the variables of "I have such and such T stat", and ect.

It is my opinion that to gain the most cooling, the atf leaves the tranny, and goes to the rad cooler, thence to the air cooler, and back, and that at each cooler the temps are dropped.

I don't know how much, hence the question marks.

................
As for my tranny frying, I am willing to take the blame for cooking it. I am not sure what was really wrong. I was plowin a large area which was narrow and working the truck in deep snow.

I fininished and drove on towards home and very near home the tranny failed. Since the tranny did not fail when I was working and the 18 miles or so towards home everything seemed fine, and this at 40 mph or so, I can't know what was really wrong.

Just that the tranny did not work well at all.. Probably the pump failed. I am not a tranny tech, and so I pulled the tranny and took it to a tech. he did not convince me that he found any certain thing wrong, but his rebuild works.

I did what I could to determine what was wrong, and didn't find anything personally.. I have had that cooler a long time, and I have a pan drain. I used a automotive paper paint filter when I drained the tranny, and found nothing. In the pan after it was dropped again there was nothing. The ATF was clean, but had a burnt odor.

This is the 2nd tranny I have installed in this truck, an on a 2nd rebuild!

The first tranny broke up in chunks in 1995, and was not repairable at all. I disassembled that one myself, and saw the carrier in many large chunks. Oddly the truck could still move, although it didn't sound any too good. Mac

[D&T Repair]

Let's hope that I never have a trans go out on me!
Although since snowplowing, I'm sure it will happen soon :(

Ah well, the fruits(?) of the snowplowing labor LOL

[Mac_Muz]

Well I hope your wrong there! I can assure you dropping and installing trannys is no fun.

I am considering a temp gauge... You might too... On line there are a few places which remark on temps allowable, but I won't swear they are right.. Mac

[wyldman]

For a plow truck,the trans fluid should go through the external cooler first,and then through the rad cooler.When plowing in cold temps,the external cooler can actualy cool the fluid too much,so the rad cooler is used to keep it at a "normal" operating temperature.

On a race car,or truck for hauling in the summer,then you want it the other way around,to get fluid as cool as possible.

[D&T Repair]

Sounds like it's hooked up right on my truck then :)
Thanks Wyldman~

[Mac_Muz]

Thanks Mac

[campi]

I hooked my trans cooler up in nov. when wyldman told me how to do it ! working very good, seeing how cold its been it makes sence that trans fluid gets real cold and needs to get warmed up thru reg rad last working for me !!! Campi !!!!!:cash let it snow!!!!plowing!

[Mac_Muz]

Ya know I wonder about that. I don't drive very fast when I plow... There is not much air movin thru that add on cooler when I am plowing.

I'ld like to read more on the reasoning... Mac

[ratlover]

JMO here.....

First if your fluid is 350 degress you have a major problem. ATF even synthetice wont live at that temp.

Second you can overcool a trany. Some tranys seem to be more pissy about it than others so I have heard. Seems to me I have heard the newer the trany basicly the more it dont like it. OD's and electric controlled ones basicly.......I've heard from a trany guy that the old 350's and 400's and such dont really care? How true this is I dont know.

Third I dont think in most of our applications you could over cool it. JMO but I just dont think its an issue. If your talking way up north and having to dodge penguins instead of little old ladies when plowing(Chris, you guys got pengins up there dont you :confused: :p ) then it might be something to think about. If you eliminate the cooler in the radiator then it might be a bigger deal in moderatly cold temps but the radiator will help it warm up a bit especially when you first start running it durring initail warm up. I dont think you will be able to get a trany "too cold" to notice any noticible accelerated wear or have the fluid be too cold for it to operate poorly. I say this because I have had tranys with no radiator cooler and a big old honking cooler in front of the radiator that was supposed to work for a motor home and it acted fine and other trucks with just external coolers and they acted fine. Also with plowing I dont see how you could possibly run a trany too cold.......lots of stress and and a big ol honking wind block. My allison runs in the normal range with just an external when plowing and traveling with a plow and thats in TH mode were my converter is locked in 2-5 gear. With the winter cover off in cold weather my trany will run just over 100* if I'm not romping on it.

JMO but I think we are splitting hairs.....but IMO runing through the radiator does a good job of geting the trany up to temp and keeping it from being too cold and it gives a slight measure of cooler fluid if you really start to work it. Dont think it would make much of a difference though.

[wyldman]

You can easily run a tranny too cold.A lot of the newer elecronic units will lockout certain functions until a certain operating temperature is reached.

[ratlover]

yes....most dont lock up till shes up to temp.

700's aint so pickey though. Its like anything else, its when they start adding all that electric stuff that stuff gets real finicky.......

never said you couldnt run one too cold, just that I think we are splitting hairs.

[Mac_Muz]

I have not found info on proper operation temps... 1 source appears as under 260 is normal.

I have no idea what really is normal. My tranny being a no electric lock up TC as far as I can tell...

I simply am asking questions as I don't know the answers..

Since my repairs there has been not signifigant snow to test on.. The repairs seem ok, as far as normal driving goes.. :huh Mac

[ratlover]

trany fluid itself wont live long at 250 or so. Its just a point of the hotter it gets the less milage you can go before you need to change it.

if you are reading 350 I would wonder about acuracy or what the deal is..... especially 350 with normal driving. Something just dont sound right to me.

[Mac_Muz]

No, I picked 350 from thin air. I had the idea, even if it was wrong the tranny temp was hotter than engine temp..

As you know a low flame heats cooking oil to very high temps...

What is the range of proper temps? I have not installed a thing on any vehical since I installed that tranny... Mostly since then it has been below 0 and not much fun fixing thing bare handed out side...

We still have snow left over from Dec, but it has never even done much in the way snow since.... just real cold...

Almost snowless winter ...Mac

[ratlover]

I would say between 120-200 is pretty normal depending on what you are doing and how cold it is. 220 or so is getting warm but nothing to totaly freak about but if are consistently seeing those temps I would chnge out the fluid often.....but most plowers do that anywho. 240-250 range is getting pretty toasty and I would try to do things to make it run cooler and change the fluid more regularly yet.

For my plow vehical that I have seen hit 200 tops I am on a drop the pan at the end of the season method(will get about 50% of the fluid out) if it was running hotter then i would go with the total flush method.

Trany temp is much more dynamic than h2o temp, mostly because the motor is designed to keep itself in a pretty narrow range. They just try to design a trany to not cook itself or run 25 degees. Trany temp will swing alot depending on what you do.

[Mac_Muz]

Now we are getting some where... Thank you...

As I recall older trannies had vents in the bell housing to get rid of heat. About now I am wishing I had made cuts of 4"x 6" and added in wire or louvers on the top where I can't reach now...

I might even do something with the inspection cover come spring.., but I am not sure what the point is when hea goes up.

Since the truck does well cold I am not overly concerned about getting the tranny too cold.. My plowing style is fairly slow, as big rocks protrude in dirt roads that I plow.

My plow is always on shoes due to that and I prefer a flat layer of rock hard ice to smooth out a road anyway...

After a storm around here it can be followed by warmer air and sometimes rain, and at below 0 it hardly ever snows with any authority. A dusting does not count in my book..

So any tranny will heat up... I guess my failure was not understanding this could happen as easily as it can...

It was rather a shock to be fine one minute and down the next with nothing to show why..... Only a burnt smelling ATF was the only signs of over heating....

I no longer trust this tranny type.... In spring I might look into a few options. I plan on keeping this truck a good deal longer..

[ratlover]

dont know if venting would help much.....I seem to remember there being a "fan" that you place between the flexplate ad the converter that supposedly helped? Dont know about that.

I think the best way to keep a trany cool is a big honking aftermarket cooler and in the case of plowing a electric fan on it might help since the plow will tend to block the airflow and most of the stress and heat you are making is at slower speeds were airflow aint the best. A deep sump pan should help a bit but I wouldnt want an aluminm pan on my daily driven plow rig although people have and dont have problems. And finding a deep pan in the plain steel variety can be hard. There is a cool aluminum pan out there with tubes brazed through it but I definatly wouldnt want that for my rig since I feel they are too at risk of whacking/cracking/puking fluid.

If you are handy with a mig and sheetmetal you could easily make your own kicked out sump pan. Just remember that your filter/pickup needs to be sitting on part of the pan to keep it from floping out. You could get all kinds of elaborate with an added sump and some heatsink stuff. And it would be a very cheap mod.

[Mac_Muz]

Well in Spring a temp gauge will go in. I don't much care for working in the temps we have been having on metalic things much.

Yes I would worry about hitting a deeper pan as well.. I do have a aux cooler..

Older trannies did once have upper vents as I recall... I can't say if they worked well or not.

I can mig weld fair, and own one, but again going lower with that pan is not much of a option for me..

It is rough going here in most places.... In fact no place I plow is paved...

I guess I am takin loosing that tranny a tad too hard. But being laid off and forking over that 700, didn't do much to improve my attititude. A bare naked x-mass tree didn't make things better..

I am married to a dear gal, and my efforts at making a few small gifts left me feeling rather cold. Dec 12th was when that tranny failed...

We are both laid off, and finding work here is grim still... We do odd jobs that don't make ends meet, and come at odd times..

Not complaining, but things could use a bit of improvement. I hope Spring brings work. Mac

[ratlover]

I wouldnt go down but if you add little "boxes" to the sided or front or back or were ever they will fit.

If your going to attempt it I would recomend finding a used pan and jacking with it so if screw it up you aint down a vehical long.

Cold weather and colder tools/parts really suck.

[wyldman]

A properly installed externally mounted trans cooler should have no problem keep that trans cool.

You could add a double deep pan for the added fluid capacity as well.

The 700R4,if built properly is a pretty stout tranny.I wouldn't worry too much about it.It should serve you well.