Tranny Coolers

[MadMax78]

I am replacing the stock radiator with an aluminum unit. I don't want to use the built in tranny cooler. What iks a good after market tranny cooler? I don't do any heavy off-roading. Looking at making it a dual purpose daily driver mild off-road rig. I'm looking for tranny coolers with no fan. All input is appreciated.

[Cassidy]

I have aways been told that you should not skip the cooler in the radiator because the heat transfer liquid to liquid is much better than liquid to air. And if you live in a place where it gets cold weather the radiator cooler will help get the transmission to operating temperature.

[tgreese]

Hayden is the best-known brand.

http://www.haydenauto.com/featured%20pr ... ntent.aspx

Follow the instructions about mounting and installation.

[letank]

Someone said once... the only place that you do need a transmission warmer "aka using the engine radiator" is Alaska. Indeed it is pleasing to think of your fluid being at operating temperature..... but in the winter that bottom radiator barely gets warm, really, it is the return cooled by the main radiator, check it next winter. The return can be from 140ish in an average spring day of 60ish to a barely luke warm on a frosty day.
So install the stand alone cooler, and in the winter you can monitor the temp and slip a rag over.... to keep it warmer...

[rocklaurence]

Go with the largest GVW you can find (related to sq inches of the unit). I've run separate coolers in my trucks for years and the transmissions all want to run between 160-180 degrees depending on load. So, if you run it through the radiator, it will put your trans fluid at approx 190-220 relative to the engine temp and under a heavy load it will quickly reach the danger zone (>240). Go with a Stacked Plate design.

[serehill]

Lots of conjecture & theory on this subject.. All brands say theirs is best. I totally agree the more you can drop transmission temp the better off you are. I also believe a single non composite unit dissipates heat better & doesn't have to have as much surface. Proven fact. An aluminum tube cooler with steel fins pressed over it will not dissipate heat like an integral single piece will. Composite units are less effective. But they're cheap. Mine certainly lost me 40 degrees in the summer over the radiator & front of the radiator type. I've never thought a unit that has constant friction would need cooling in my geography. Not many manufacturers advertise the actual dissipation capabilities of their systems. My opinion remove it from the radiator get it in the air & find something that dissipates well & you won't need a giant unit to make it work. Your engine & transmission will thank you. I have to agree Hayden has a great name in composite units but you can't find much literature to really compare.
Most of their deigns are 50 years old & things have changed in the engineering field since then. My solution has served me well but catches peoples hair on fire. Just my opinions this old dog learned some new tricks with the coolers.

Just my 2 cents.

[MadMax78]

Does it matter if it is mounted to the radiator or is it better to have it mounted by itself?

[ScottsMojo]

Does it matter if it is mounted to the radiator or is it better to have it mounted by itself?

FWIW, this is how I did it and I have no cooling problems, towing wheeling or otherwise. Take a look and decide for yourself...

http://fsjnetwork.com/forum/viewtopic.p ... oler#p1390

[Mdcptman]

http://www.ifsja.org/forums/vb/showthread.php?t=170711



http://www.fsjnetwork.com/forum/viewtop ... 566#p68566


This sparked some controversy when I posted it, but its working great, and has been an excellent solution for me and others here.

[Southern Gorilla]

If you're worried about over-cooling in the winter you can always put a bypass line in with a high-pressure valve to switch between the cooler and the straight line. But I'd definitely go with a separate cooler over the built-in one. The built-ins just don't make sense. You're using hot water to try and cool the transmission and you're dumping more heat into the coolant before it goes back to the engine. But those are cheaper to produce and easier to package, so that's what the OEMs use.

[MadMax78]

Wow! Didn't realize there was so many thoughts on these. I can see everyone's side though. I am in Central Arkansas so not many -0 days. I am going to try it and see what happens. Thanks for the input guys. Here is the one I have decided on. Any thoughts? It supports a GVWR up to 30,000 pounds, towing up to 10,000 pounds. Surely I will never max it out.

[fulsizjeep]

I am not a big fan of the goofy zip ties that hold an aftermarket cooler to the radiator through the fins and prefer one mounted differently like the stock Bodine units used on 80-91 FSJs.

[chevelleguy]

I am not a big fan of the goofy zip ties that hold an aftermarket cooler to the radiator through the fins and prefer one mounted differently like the stock Modine units used on 80-91 FSJs.

^ fixed it

[fulsizjeep]

Thanks for the typo fix David. Definitely not a Jethro item.

[MadMax78]

Thanks for the help guys. Going with the one pictured above mounted separate from the radiator.

[FSJunkie]

I was once was very concerned about the trans running too cold in winter. I actually plumbed my transmission coolers so the oil went through the auxiliary cooler FIRST then through the radiator cooler second to warm it up before it returned to the trans.

But honestly, can anybody name a vehicle that did it this way? I've always seen them radiator cooler first then the auxiliary cooler. There is a reason things are plumbed this way, it's not just coincidence. This is so the radiator knocks down most of the heat from the fluid before that heat gets put out in front of the A/C condenser. This increases A/C performance. Also, with things plumbed this way, the aux. cooler has a chance to cool the fluid below the radiator temp, which is very useful if your engine happens to be overheating that day. The engine may be overheating, but at least the trans stays cool. That wouldn't be the case if the trans fluid went through the radiator last, as this would raise the trans temp. Now both are overheating.

As for condensation in the fluid,

Even though the fluid leaving the trans and heading for the coolers might only be 100 degrees or so on a cold day, the temp the fluid actually sees inside the torque converter is far above that. The average fluid temp leaving the converter may be reasonably cool, but some of that fluid saw very high temps inside the converter and has diffused its heat to the rest of the fluid before it even leaves the converter. This is sufficient to cook out moisture.

[serehill]

Yeah if all that theory is true then Mdcptman has got the best solution. But then I already knew that after 5 years of proving it know he does.

Fluid can not come out of the radiator at any less temperature than the engine coolant.

[fulsizjeep]

fyi, Modine unit

[FSJunkie]

fyi, Modine unit

Gee, isn't that the stock unit?

Wasn't that thing's use just THEROY?

[fulsizjeep]

If the turn signals still work after installing a Modine, should be good to go. Otherwise use the Bodine.