Looking at doing a circle d 3200 soon and adding a trans cooler. Should add the cooler in line before or after the stock cooling system? Or does it not matter. Sorry if thats a dumb question, im new to working on cars.

 

Use the cooler on its own.

 

Use a plate cooler by itself.

 

After the stock cooling.

 

Many threads have covered this topic endlessly.
The "near" consensus is to bypass the stock cooler in hot climates, and after the stock cooler in cold climates if the car is driven in the winter.
Since you are in Houston TX, the "near" consensus would be to bypass the stock cooler.

 

In Texas......bypass the factory tranny HEATER....its NOT a cooler by any means. Your tranny temps will be higher if you use it.

.

 

Yes a cooler rated for at least a 29000 lb motor home if I go into use without factory cooling system. The fluid must get warm enough on a regular basis to burn off its own pollutants to keep the fluid clean.

 

This

 

I don't think it matters if it's before or after the stock cooler. To those saying to ditch the factory cooler, I have no idea how anyone is getting away with running just an aftermarket cooler unless it's enormous and has its own dedicated fan. I've tried it both ways and without the factory cooler in line my trans would overheat when idling or driving slow for extended periods, like sitting in a long fast food line or in rush hour traffic. That's with a 3200 stall. Put the factory cooler back in line and the temps went back to what they should be.

 

Well not everyone has the same experience as you. When mine was on the condenser I ran it both ways. With the stock cooler it got to 185ish pretty quick on a hot day. With the stock cooler bypassed it would get to 185 but took a hell of a lot longer, indicating the stock cooler acts as a warmer...and why shouldnt it, its using the coolant to keep the trans in check and the coolant runs 200+ all the time.

 

I have this in addition to original

 

There seems to be quite a bit of differing thoughts and opinions about external (auxiliary) transmission coolers. What type, how to run them, and where to place them. Many years ago we did some comprehensive testing of external coolers to answer all the questions. These tests were initiated by a Grand National we had in the shop that kept overheating the fluid and blowing it out the vent. The first step was to make certain that it wasn't any type of internal trans pressure leak, so we actually swapped the whole transmission, but still had the same exact issue. Next, we installed a large "tube and fin" external cooler. The problem was still there. We then installed 2 external coolers, ran in series. The problem was still there. At that point, we decided to install temp gauges on the in and out cooler lines. What we found was disturbing. The fluid coming out of the cooler (s) was hotter than the fluid going in. The series of tests proved that only using one cooler didn't heat the fluid as much, and that running through the factory radiator provided substantially better cooling.
After spending a week, trying to figure this out, we were directed in the direction of a "stacked plate" cooler that was actually smaller than the first "tube and fin" cooler. The "stacked plate" cooler fixed the car, and actually cooled the fluid. We knew that effect, but were puzzled by the cause. Some research (and some common sense) led us to the reason. Think about a "tube and fin" design. It's basically a tube that has a series of 180 degree bends that run through series of fins. Now, think about fluid dynamics. Everytime fluid is asked to change direction rapidly, it produces more pressure. Pressure generates heat. This also explains why using a larger or double "tube and fin" style cooler generates even more heat.
As stated, the test also confirmed that running your cooler lines through your factory in radiator cooler first, provides better cooling. We have confirmed this countless times since . A "stand alone" cooler just isn't adequate to keep the fluid cool enough on a street driven car. I've proven this theory to many customers, via the use of a n infrared heat gun.
Cooler placement is also critical. We've seen people who place them in places "where air can pass through them while driving". The only time you can mount a cooler anywhere other than directly in front of the radiator/condenser is if you're using a dedicated electric fan. When a cooler is mounted directly in front of the radiator/condenser, it uses your stock fan (s) to pull air through the cooler while the car isn't moving. In a normally operating transmission, the torque converter produces the largest majority of the heat. It produces the most heat while it is stalling (slipping). The converter is stalling the most when the car is sitting still.
Testing an experience has led us to the conclusion that the Tru-Cool 4490 cooler (11"x12"x3/4"), ran in series, mounted directly in front of the radiator is sufficient to cool a street/strip car with very high stall converters. Obviously, there are others whos results may differ. I can only suggest what I've learned from personal experience and testing on a high number of various vehicles.

Frank

 

Above is an article I wrote for another forum. One thing I left out is that the fluid should be ran through the factory cooler first. The bottom line from the 4L60E transmission should not be interrupted. It should run constant between the transmission and radiator because it's the feed line. You should then come out of the radiator, into the auxiliary cooler. Out of the auxiliary cooler back to the top line of the trans.

Frank

 

A tube/fin cooler is less restrictive than a stacked plate cooler.

The bends in a tube and fin cooler aren't going to cause fluid to heat up.
Cooler line pressure isn't high enough, nor is there enough flow for that to be even remotely a cause. That's a laughable theory.

I have a good idea what the cause was of your mysterious fluid getting hotter through your coolers.

 

My temps changed as indicated above by a very simple change, eliminate the stock cooler with no other changes. If I know the fluid heats quicker using the stock cooler, and it should, eliminating it helps keep the temp down. Moving my cooler off the condenser caused a massive increase in temp, thus absolutely necessitating a fan, which is how it currently still runs. A fan is only required in the hottest few months of the year, as that's when I initially moved mine and saw the drastic temp spike. This proves airflow is absolutely critical in disappating heat, at least with a solo external cooler.

 

And the statement of needing a stock cooler to keep temps in check I find false, as lots of people have disproven that theory a heck of a long time ago. A single independent unit can do the job just fine, maybe even better. I was lucky enough to install my temp gauge first, then I had stock cooler, stock cooler + 70264, then 70264 by itself, then 70274 (bigger) with braided line by itself, then 70274 moved to the bumper, and finally the 274 in the bumper with a fan. I have monitored temps throughout all these changes, so thats what im basing my figures from.

 

What's the good idea of the fluid getting hotter???

 

There is no way a cooler is going to increase the temperature.
I wonder if you had the In/Out lines to the trans mixed up and were therefore measuring on the wrong side. The 200-R4 is opposite of a 700R4/4L60E.

This table shows which cooler line is In/Out for each transmission:

http://www.txchange.com/cooler.htm

Coolers cannot possible heat the fluid.
Every other "shop test" reported here came to the opposite conclusion.

OK, reasonable.

Not quite. Constricting a passage increases pressure and temperature. But as soon as it opens up again, i.e. straightens out, the pressure and temperature drop. The longer the run through any cooler, the more chance the fluid has to cool to the ambient temperature. Perhaps you measurde temperature at places where the tubing was different in diameter - that would skew the results.

Sorry, but I am confident that is simply false.

This is true. You would never want to run through the extra cooler first and then the radiator cooler as that would likely heat the fluid as the ambient temperature of that cooler is often 200F+.

While it might be true is some cases, depending upon the engine's thermostat temperature and other factors, it is not consistent with the experience of many other members here.

All true.

If you mean just idling, that is false as the high stall converter is then producing just as much heat as a stock converter. A high stall converter produces more heat especially in city driving because the engine is often at a much higher RPM and throttle position than it would be with a stock converter.

That is a reasonable cooler size, but I know many will disagree with running it in series with the stock cooler.

Also to quote someone from another forum:
"Ive had the coolers crack inside the rad twice now, immediate death of the trans,"

(From http://www.thirdgen.org/forums/ltx-l...line-flow.html)

As a moderator, I'm not inclined to be so "disagreeable", but much of this is the opposite what I am confident are facts established over the thousands of posts I have read here over many years. Several experts who wish to remain anonymous also PM'ed me about the inaccuracies.

While I humbly disagree with some of the statements, I know you are trying to solve the same problems as all of us and a discussion and personal experiences are encouraged.

 

A Grand National uses a 200-4R, and as mrvedit mentioned, the cooler line outlet/inlets are opposite most other GM RWD transmissions.

The testing method was flawed due to misinformation. Fluid cannot get hotter in a "cooler". If the fluid temp seemed to get progressively hotter as it went through each cooler, common sense SHOULD tell you that something is amiss.
If it shows to heat up through two separate coolers getting hotter as it goes, my first instinct would be maybe the fluid isn't flowing the direction I think it is not come up with my own version of fluid dynamics.

 

Damn that was a long post