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Tranny Coolers

5K views 43 replies 26 participants last post by  frog_dude 
#1 ·
The tranny cooler on my car , I have the fluid going through the rad first, then out to the cooler . I read somewhere , if you drive your car mostly in the summer , you don't have to run it through the rad first. Let me know your thoughts.

Dave

http://i126.photobucket.com/albums/p87/Dave427/SAVE00802.jpg
 
#3 ·
Lots of debate on this one and a couple of schools of thought. I run my rad cooler after the aux cooler. The theory is dump as much heat out of the tranny fluid as you can, and then allow the radiator temp to moderate the fluid temp. It prevents the tranny fluid from being too cool, helps it warm up faster, and moderates the temp swings.

Others will tell you this is backwards.
 
#13 ·
Not me. I say this is the preferred method. You use the add-on cooler to dissipate the excess heat, then you use the engine coolant to do the "fine tuning" of trans fluid temperature. Trans warms up quicker which helps to moderate the excessive line pressures in a cold trans. There's no chance of over-cooling the fluid in cold ambient temperatures or at light load.
 
#12 ·
Ok i guess the question here is if you run the hot trans fluid through the radiator and you have a 180 thermostat in, the trans will not fluctuate far from that temp? If you like to drive far distances, then like to take off hard from every stop light (he he) then putting it through the radiator then to the external cooler you get a much greater heat dissipation into 10-12 Quarts of antifreeze than say through the heat dissipation through just a stand alone cooler will give you.
 
#15 ·
Good timing with this post. I'm in the process of putting a new aluminium rad in my car, and it doesn't have a cooler in it. I'm running a external cooler right now (11 x 7 1/2) about 19000 GVW (stacked plate design). I'm also planning on running this as the only cooler. I have a 2800-3200 stall convertor in a TH350. Will this cooler size be sufficient? What size coolers are you guys running? Thanks for any info.
 
#18 ·
Water dissapates heat much more efficiently than air. Use both! I know many have had no problems, but it depends on your driving habits. Unless you use a trans cooler with a sensor and an electric fan attatched to it, you get nearly ZERO cooling in heavy stop and go traffic.....just my .02
 
G
#20 · (Edited)
I disagree and it would seem most of the OEM's do too since the fluid goes through the radiator and then the auxiliary cooler in all the applications I've seen.

I think there is also a misconception that the engine coolant heats up faster than the trans fluid.

Dana Corporation, an OEM supplier, and manufacturer of Tru-Cool brand transmission coolers (also sold under the B&M and other brand names) says this about installation:
"Where should I install the cooler? If possible,
locate the cooler in an area where it will be exposed to
ram air. This helps maximize cooling. Install the cooler in
series and downstream of the radiator in-tank oil cooler."
 
#21 ·
Can't believe everything you read... I like the idea of the oil cooled in the factory cooler after the aftermarket to help maintain and average temp. It's like a fuel system, the pump does excess work too keep a plentiful supply of fuel, and then the regulator well... it regulates how much pressure that line will maintain.
 
G
#23 ·
A fuel regulator doesn't regulate heat it regulates pressure. Obviously completely different.

If you route the auxiliary cooler before the in-tank cooler, you will be cooling the fluid to probably re-heat it depending on conditions.

An automatic transmission with a STOCK large diameter converter produces enough heat to bring itself up to operating temp faster than most engine/cooling system combos.
Watch a coolant temp gauge and trans gauge from a cold start (~20-30*) normal load condition sometime.

Do you know where the fluid leaving an auto trans is coming from when it enters the cooling circuit and what it is going to after it returns?

It's not "believing what you read", it is having an advanced knowledge of the way the components work as well as extensive experience specifically with automatic transmissions.

The OEM and trans cooler engineers must have it all wrong :clonk:
 
#24 ·
I ran all summer, aprox 3000 miles of non-highway driving, with an ATI 10" 3200 converter with only a B&M super cooler. Even after long, slow drives you could touch the trans pan. No overheating at all.:thumbsup:
 
#27 ·
I must ask... what is better or worse for an auto tranny, under cooled tranny fliud through a external only cooler or tranny fluid that is regulated through that dang hot radiator cooler when not used in tandom together?

My neihgbor with a 79 ford 460 camper special and auto tranny pulled a big fifth wheel camper to Nevada every winter over the mountians and has for years with over 150000 miles on the never rebuilt tranny with only a external cooler and the tranny still works perfect.
After rebuilding the engine and getting an oversized radiator with no provisions for the tranny lines he would be one to tell us that external only cooler would be fine. HMMMM....
 
G
#28 ·
Few key points to your post,
Your neighbor towed in the winter, where it isn't as hot. That helps alot. Secondly he likely did so at some speed, so there was (I'm assuming) airflow over the cooler.

As I stated,
a stock vehicle (usually produces less trans heat than a modified performance car with a looser converter) will heat the trans fluid faster than the engine will heat the coolant.
I have experienced this on several different stock and modified vehicles, so tend to believe it is normally the case, although probably not always.
So the common belief that the engine coolant will help to "warm-up" the trans fluid is generally not the case.
The posted that stated liquid cools better than air has it correct.
The thermal transfer to a liquid is better because it is denser. There is also forced flow in the in-tank radiator cooler, even when a vehicle is not moving.
This is why using the in-tank radiator has it's advantages.
However the average performance car is likely running a 180* thermostat, and most modern vehicles run a 195* t-stat.
The trans cooler portion should be on the "cold" side of the radiator and hopefully there will be a significant temp drop by the time the coolant gets to this side but even at 140*, it may not cool the trans fluid adequately before it sends it back to the transmission.
The fluid is coming directly from the converter circuit so in some cases may be HOT, much hotter than trans pan fluid temps. You need to cool it off as much as possible before returning it.
Routing fluid through a auxiliary cooler and then to the radiator is defeating the purpose of using the auxiliary cooler. This is why the OEMs do not do it this way.
It would be very difficult to "over-cool" transmission fluid. By design it is relatively light oil for good lubricating and cooling properties at a wide variety of temps.
The exception to this rule might be someone who lives in a very cold environment, where average daily high temps rarely exceed freezing. However the technology now allows the auxiliary cooler to bypass and not cool the fluid.

There are some cases where following the crowd isn't the right thing to do, you can never excel if you do things the same way they've always been done, however, transmission and even oil coolers have been pretty well thought out by the auto manufacturers and unless you have alot of time to waste trying to disprove their methods, I would recommend following their lead.
 
#30 ·
Thanks Jake,
You are correct...he traveled in the fall and spring.
He also was one to do a little over the speed limit as he said it gave him better miles per gallon.
I will add that he bought the truck new and had it serviced by dealerships only so the truck was well taken care of... I will add that I am glad of that, because I am the second owner of that truely rare truck and I am not a ford guy but could not pass it up when he finally cracked and said he would sell it to me.
Of course It was a truck that I had to restore back to original cond...I loved this truck for pulling my boat, unlike pulling with any vehicle under 40Gs nowadays. If I can find a pic I will post for all to see.
Worst part is, is that I no longer use the truck and am going to hate to see it go to the ford truck lovers... as I am going to be selling it as soon as the weather gets clean up this spring.
Dan
 

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#32 ·
[. I'm running a external cooler right now (11 x 7 1/2) about 19000 GVW (stacked plate design). I'm also planning on running this as the only cooler. I have a 2800-3200 stall convertor in a TH350. Will this cooler size be sufficient? What size coolers are you guys running? Thanks for any info.[/QUOTE]


im runing the same setup with same stall............havnt had any probs...........if anything the fluids a little on the cool side.
 
#33 ·
LoL! It does seem strange when you get different answers from different people- especially manufacturers!

The one I choose to believe is where the fluid goes through the aux cooler first, where much heat is shed, and then through the radiator cooler where the temp is regulated to proper operating range (more on that later).

Just a notional example: If a tranny is making the fluid, say, 220 degrees then it is going to lose some heat going through the aux cooler. How much? Who Knows for sure- every car is different. Lets say that it drops to 140 degrees. Then, it will be warmed back up in the radiator to whatever the coolant temp is in the bottom of the radiator. This helps cool the coolant (good!), while bringing the tranny fluid back to good operating range of about (depending on whose numbers you choose to believe) 160-200 degrees.

If the fluid goes through the tranny first, it will impart heat to the coolant (not the best of circumstances, when you are trying to shed heat) and then lose more in the aux cooler. What is the temp of the fluid then? Who knows? It is unregulated- unless you run a thermostatically controlled system. There is a good chance it is too cool, especially in cooler climates.

We can, and have, been successful using either scheme in warmer climes, but will a tranny last longer if the fluid is run cooler than the recommended operating temp? What is the difference, if any, in the life of the tranny?

Cooler is not always better for either tranny or engine oil.
 
#37 ·
My tranny shop says... Radiator to ex cooler back to tranny.
Had to ask as I was talking to them today because I lost a tranny in my olds because of the JUNK probably the (plastic type) is my guess, radiators GM and others make!
Lost tranny fluid into the radiator a while back... which likely led to some radiator fluid finding its way back into the tranny and you guessed it... helped in trashing the tranny sooner rather than later. (keep your eyes on those over flow tanks folks!)

I put universal ex cooler $32, on it that got me buy for awhile plugging and bypassing the radiator that cost over $220 to replace ...but at idle and no full time electric fan( mentioned earlier in this thread and needed/should have had) the fluid got to hot and helped finished er off...mainly, I believe due eccess heat at Idle and stop and go traffic and warm up idle in cold weather(wifes car, and she dont like being cold) so you know what that means (long warm up times so her butt would not get cold)
Tranny shop said there are certian ex coolers that will work alone without going to radiator first but they are specific for different applications? Live and learn!

Sold the car today but for only half of what the price was set for yesterday...in my case it was a no win situation but I felt lucky to get rid of that ride as it was going to be sold after winter anyhow.
 
G
#42 ·
Long is a division of Dana Corp.
Tru Cool is a specific model of cooler made by Long.
(http://www.dana.com/Automotive_Systems/images/PDFs/TC_Brochure_2004_Website.pdf)

I use Eaton and Dana interchangeably due to their being tied together in the manufacture of drivetrain components and having recently sold parts of their businesses to each other.
http://www.eaton.com/EatonCom/SearchResults/index.htm?ssUserText=dana&x=0&y=0


So in essence,
B&M's coolers are Tru-Cool, Long, Dana, whatever you want to call it, same parts.
 
#43 ·
So in essence,
B&M's coolers are Tru-Cool, Long, Dana, whatever you want to call it, same parts.
Cool. I though Long was independent. Had the impression they were based in Canada. Thanks for the correction.
 
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