You are entitled to your opinion.. It just isn t same as mine..check with any cooler manufacturer , trans builder , TCI, Bowtie, Monster... all recommend using Radiator heat exchanger first then cooler in series.. taking 200*+hot fluid down to 120* or so in radiator before going thru the auxiliary cooler can only give you cooler fluid coming out the auxiliary .. and a cooler alone is NEVER recommended in cold climates at all.. .. ... but you do what you like , its your car... My 700r4 runs a nice 150* in August in 110* heat down here in traffic

 

I thought about this subject for hours recently. If we were having a beer, here is what I would say.

I would find a place to mount the largest cooler I could get. I would also want to have a fan on it to prevent heat from building up at stop lights. Space to allow the air to flow helps and popping it in neutral at lights doesn't hurt.

Do you live in a warm area or cool? I live South and it has hot summers and mild winters.

Does your radiator have the trans cooling tank or not?

Do you have air conditioning?

I have a Th2004R transmission running through a stand alone tube and fin cooler like you are looking at. I installed a gauge sensor in the pan and think of 150* as my red line.

I initially had it mounted directly on the radiator with a puller fan on the radiator. After an hour long drive and some hills it would start to heat up at a stop light if I did not get moving. It would climb past 150*.

I then mounted a small fan directly to the cooler. The fan was set to come on when the engine temp. goes over 180*. I thought this would help at stop lights but it was marginal.

Finally, I went with the setup you see below. There is a space between the radiator and the cooler and a pusher fan on the cooler. This is what I ended up with.





The electric fans only come on at stop lights and the temps are usually between 100 - 130 in the pan.

I think you will want a larger/better cooler for a TH400 as a stand alone. If it is an auxiliary, it will probably help bring pan temps down 15-20*.

http://trucool.com/products/tru-cool-lpd Those coolers have a bypass to allow it to get up to temp if that is a concern.

 

You are correct that most of the recommendations from cooler manufacturers and transmission manufacturers state to run the cooler in series with the Stock in radiator cooling..no dispute there. This setup will lower the temps adequately for most applications but is not the optimal setup for maximum cooling of the fluid. I would say based on my experience of 30+ years using coolers that 145-150 degrees is the maximum temp you want the fluid to reach for the longest tranny life. I would strongly recommend against tube and fin coolers since they are not the most efficient at cooling versus a double stack plate cooler like Long/Dana AND the Long/Dana coolers have built in temp control in their design. The question remains why some manufacturers like my Chrysler 300 use an air to air tranny cooler alone from the factory if the air to water cooling method is always the best application?

BTW-I have never had a tranny failure in ANY car I have had external only transmissions coolers in 30+ years....real world results versus theory....

 

I thought about this dilemma long and hard for my cars with electric stock fans that do not run all the time. For cars like my C3 and my 73 Nova SS with a stock mechanical fan running all the time, the tranny cooler outside of the radiator cooling is ideal since air is always being pulled over the external cooler. For cars with stock electric fans like my Mustang GT and Grand Prix that do not run all the time, I went oversize on the coolers (2 coolers one with 36,000 GVW cooling and the other 42,000 GVW cooling) along with the built in temp control design of the Long coolers. In the cooler running temps with the fans running occasionally in non highway driving, zero issues. In hot weather, the fans either run more often or with the AC on in hot weather, the fans run constantly resulting in 135 degree trans fluid temp in the GP and 140-145 in the Mustang. The Mustang and the GP before the coolers were installed ran VERY HIGH tranny temps with the radiator only cooling-both the ford AODE and GM 4T65E trannys are known to run VERY HOT which shortens the tranny life significantly. Side benefit in both cars is the coolant temps in all weather is noticeable lower since the radiator does not have to cool both the coolant and tranny fluid. I do know that in heavy duty diesel pickup applications and police packages that run external only tranny coolers that the fluid from the FACTORY will run 110-115 degrees in cold weather on the highway all day long....so much for running the fluid too cool...Hmmmm

Two things I know for sure:

1. Change the fluid and filter often...NOT what the manufacturer recommends if you want max tranny life..dirty fluid is the enemy of a transmission. I am also adding a remote oil filter adapter (uses a 1 QT oil filter) on the 300 when I install the external cooler for additional filtering capability as well on the upcoming install...used this method on the Nova SS as well 30 years ago. The stock in pan filter is marginal at best....

2. Use an external cooler of some sort for long tranny life.

 

I agree stack type is superior..no argument there.. I also had a Dodge with their standalone cooler OEM...trans was rebuilt twice, once under warranty, and once at my expense.. was always slow to shift in real cold weather .. As to why they did it....COST would be my guess , only one radiator needed regardless of transmission...GM refused to pay $0.46 to fix an ignition switch flaw and over 100 people died! COST! I ve had excellent results using them in series as recommended... Its hard to teach us old dogs new tricks... good discussion tho ..

 

On a cool weather day, my 6l80 in my F150 will run 140-150* for a long time... Unless I'm doing a lot of stop/start. I think as long as the fluid is "warm" (>100*), it's gonna flow fine and the transmission will work great. Cool fluid doesn't bother them, it's the hot fluid and reduction in line pressures that cause the issues.

You really want to keep the trans at 200* or less...

A good stand alone cooler will work well for that. If you run the atf through the radiator, and your engine is running 200*+, odds are, your tranmission is too... Heating it up for nothing.

Now if I was in a really cold climate, like Alaska or Canada, I'd probably run it through the radiator to help warm it up.


All of this BS being said, a good TH350 or TH400 doesn't really care either way. They are not nearly as critical. Put a cooler on it and forget about it... I don't even have a gauge on my T400. I have 18k miles, eighty 10 sec 1/4 mile passes, and COUNTLESS highway passes on the street, it always works fine.

Now overdrive transmissions are another story, you have to keep a close eye on temps on those, you really want them to stay as cool as possible. 160-190* max...

A lot depends on the torque converter stall speed you have.

In my z06, I run a 4l60e, a 9.5" converter that flashes to 5200 rpms... I keep the trans at 170* or less at all times. The b&m 70297 cooler with the fan does this easily, even in summer when the engine temp is 230+. That's why I keep the coolers stand alone.

 

I was in the transmission business for several years. The radiator will suffice for cooling and there is no need for additional cooling unless your modifying the car. OR you have a chevy Blazer / S-10 from the early years with a 700R4 and you tow a camper. In that case your trans will be fried and the only solution is a rebuild and an external cooler which if I remember right GM recommended after thousands of warranty claims ,TO be installed independently of the radiator ..

In any performance car or truck and we did plenty of tow trucks we always used the aux cooler independent of the radiator. The reason is simple , you have much more cooling area and a direct heat transfer to the air. You also protect the trans from any potential motor over heat as well as a cooler failure which is rare but can destroy the trans.

In any car with a stall converter ( I have 4000 ) we always ran the cooler stand alone for the same cooling benefit I stated above . In my ride on hot days with spirited driving my trans has never gone above 178 degrees. ( 4L80e with lock up )

 

I mounted mine in the nose above the holes that let air in as I needed all the cooling I could get at the time. Also used one of these style coolers.

 

LOL....I had a '72 Nova with a nitroused big block and a T-400. Sloppy as heck converter and 3.08 gears. To give you an idea of slippage...I later installed 4.11's and the finish line RPM was identical!!

Anyway, that poor thing ran around with the cooler ports tied together with a loop. Temporary deal that I never got around to fixing. Not saying I was proud of it, but that stupid thing ran for years and years and years without an issue on the street and track.


I would agree that if I was daily driving it in sub zero temps...maybe a radiator cooler in series would be a benefit.


JIM

 

Well..I want to thank you for all your inputs...I live in Virginia and dont drive the cat in the winter months...so I guess my best option would be an external/independent cooler w/fan.

any suggestion as far as brands?..summit carries a good size "Derale performance" 13750 . anybody has this set up with the rear end mounting?...if yes ..pics please

http://www.summitracing.com/parts/der-13750/overview/

We'll call it OIL COOLER MOUNTING IDEAS

Thanks!

 

You don't need an electric fan with a C3 corvette as long as you have the OEM mechanical fan that operates all the time and you mount the cooler so that air is pulled through it at all times and idle. Long/Dana are the ones that I have used for years...I have 4 Long coolers on 2 of my cars and I am about to add a 28,000 GVW Long/Dana cooler on my Chrysler 300 as a stand alone cooler (note Chrysler 300's run the OEM AIR to AIR trans cooler utilizing the bottom section of the AC condenser as the cooler...no interaction with the radiator coolant). Long/Dana coolers are used by 9 out of 10 auto OEM manufacturers as an OEM cooler in applications that require a cooler. They are pretty darn good and durable PLUS have a built in temp control. Read here:

http://www.ebay.com/itm/LONG-4590-TR...ZRDGP3&vxp=mtr

 

I believe Tektrans has one like that mounted in the rear of his car.

 

Here is my setup mounted under the tank where I do not have a spare tire. I live in South Florida where heating up anything is not needed only cooling.




Since there is no exhaust or engine heat back here it keeps the trans nice and cool.

 

So I decided to have the trans. cooler w/fan mounted in the back for more clearance and air. Now... since I received the wrong size SS hoses I had to run to PepBoys and buy the ProFlex SS braided hose they had in stock...is this a good choice for transmission lines?
https://www.pepboys.com/product/details/9958850/00745

Thanks

 

Best of both worlds-bypass radiator AND run in series.

 

more pics?? se whatch you got