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AW4 transmission cooler

The Box

The Box

NAXJA Forum User
Location
Knoxville
I am looking to install a transmission cooler. What is a good setup, or anything I need to know when considering options. I've seen alot of options on ebay from aluminum finned lines to small radiator type coolers with electric fans on them. rangeing from $35-$200. Anyone have any experience with this?:helpme:
 
You just need a small unit that you pick up at any Auto Zone type place. Last time I looked they were cheaper than that and on the shelf for you to look at.
 
Since there is minimal air circulation when crawling offroad, is it enough to keep the oil cool without having a fan?
 
The OEM Trailer tow package kit is pretty good and its "plug-n-play".I just tossed one for a larger plate cooler since I bought a trailer.
 
99Cherokee said:
Since there is minimal air circulation when crawling offroad, is it enough to keep the oil cool without having a fan?
Click to expand...
You mount it in front of your radiator and your fan pulls air thru it. If you unplug your air conditioner compressor then turn it on AC inside the cabin then your electric fan will come on without running the actuall air conditioning. This just gives aditional air. If you don't turn it on it will eventually come on but I don't like to wait untill it's that hot. My 98 had the factory cooler on it. You need to make sure you don't allready have one. It mounts low behind the grill and is about 4"x14".
 
Thanks for the input. I will check tommorrow to see if there is one there already. It is a '99 limited and it has a hitch, I just don't know if it has an original tow package that would include the cooler. As far as unplugging the compressor to control the fan manually, do you mean just unplugging the wires so it doesn't turn on? Thanks again for the help.
 
Yep. It's just one wire going to the compressor. When your done wheeling or towing you just plug it back in and you back to A/C. People have come up with all kinds of switches and automatic controllers but this way keeps it simple. The computer sends a signal when you turn on your A/C to turn on the compressor and the electric radiator cooling fan. You just stop the juice to the compressor but the fan turns on. Works great. I hope you already have the trans cooler. Good luck!
 
We are having a discussion about AW4 transmission coolers over in OEM Tech Forum... I am looking for some more feedback from the members that are active in modifying their rigs.

http://www.naxja.org/forum/showthread.php?t=942618

Specifically, I would like to know if you install your transmission coolers like the OEM does, in the return line, (after the radiator cooler) or in the supply line, before the radiator cooler?

I'm not trying to beat a dead horse here, like the DEXIII vs ATF4 threads. I'm guessing there are situations where there are times when you would want to do it one way, and then times you would want to do it the other way. (or maybe not).

Thanks for the feedback in advance!

McQue
 
From what I have read and understand it may be best to bypass the rad to cool the tranny fluid. When I installed my new rad and tranny cooler a couple years back I completely bypassed the rad and just ran the tranny lines through the tranny cooler. The idea of course is that the additional heat from the coolant running through the rad does little to actually cool the tranny fluid. I'm no expert but that was what I learned in my searches. Now I have the taurus fan drawing air through the rad, tranny cooler, and ac condensor. I plan on removing the ac lines and condensor soon with my oba system because the ac condensor is pretty constricting for air flow so I believe that when I remove it it will also make a large improvement in air flow.
Just my opinion.
 
Stumpalump said:
Yep. It's just one wire going to the compressor. When your done wheeling or towing you just plug it back in and you back to A/C. People have come up with all kinds of switches and automatic controllers but this way keeps it simple. The computer sends a signal when you turn on your A/C to turn on the compressor and the electric radiator cooling fan. You just stop the juice to the compressor but the fan turns on. Works great. I hope you already have the trans cooler. Good luck!
Click to expand...


Fine for you living where 85 degrees and 5% relative humidity is a hot day. Not so good for the OP living in Atlanta.... If he does what you describe his A/C is non-operational then. He won't be happy when its 95 degrees and 90% relative humidity out....

Installing a switch is extremely easy. Takes about an hour, around $15 in parts, and most importantly leaves the A/C operational....
 
I put in a B&M tranny cooler with a B&M Tranny fluid gauge. i plumbed it did go through radiator still. its worked great, and according to my gauge, the fluid hardly ever gets above 100* or so. i put my tranny cooler right infront of the fan thats always running on the passenger side of the radiator
 
To turn on the aux. fan, all you have to do is set the blower to either the windshield only or the winshield/lower setting. That will cycle the fan--if it doesn't, you have something wrong or an older model.
 
There is really no sense to running the fluid through the radiator when you have an external cooler. Since the radiators job after all is to keep the coolant around 200deg's, it actually does more harm than good. The job of the transcooler however, is to cool the ATF as much as possible to maintain the highest line pressures.

Simply plug the holes on the radiator, and route the lines for the external cooler.
 
bmyohn said:
I put in a B&M tranny cooler with a B&M Tranny fluid gauge. i plumbed it did go through radiator still. its worked great, and according to my gauge, the fluid hardly ever gets above 100* or so. i put my tranny cooler right infront of the fan thats always running on the passenger side of the radiator
Click to expand...

What happens in the winter when the temperatures get real low, what is your temperature?
B&M are supposed to bypass cold fluid and not cool it any further, I never figured out how that happens.
 
Timber said:
To turn on the aux. fan, all you have to do is set the blower to either the windshield only or the winshield/lower setting. That will cycle the fan--if it doesn't, you have something wrong or an older model.
Click to expand...
that is because those settings run the AC to help defog the window
 
I know. I just thought I'd mention it since others were talking about messing with wires and switches to make it cycle.
 
falcon556 said:
What happens in the winter when the temperatures get real low, what is your temperature?
B&M are supposed to bypass cold fluid and not cool it any further, I never figured out how that happens.
Click to expand...

It sits right at about 100* according to my gauge. If it gets cold enough (which it doesnt really in Southern Indiana) the radiator will "heat" the fluid a little bit more.

From what I have heard, the B&M has a "switch" of some sort, that checks the viscosity of the fluid. If the fluid is thick (cooler) it will bypass the fins of the radiator, and continue throught the tranny radiator. When it is hotter, the fluid is thinner, therefore it will go through the entire cooler and cool the fluid.

The reason i put mine to run through the radiator, is because that is how it comes from the factory (except i put mine on the opposite side of the radiator, where it should be out of the factory). I havent had a problem with my tranny overheating (which it did at one point when i drove out to Mass. to Indiana when i moved (hills of New York = not fun for AW4, 31s, and 3.55s @ 75mph uphill...lol))
 
What cause overheating in the first place? Lugging the engine,what else? I know when we go snow bashing some guys think 4Hi is better for traction and those are the ones that boil tranny fluid. Whats the sign of an overheated tranny? Some puke fluid from boiling the fluid but I have never seen or herd of an XJ puking tranny fluid when hot. I still carry extra fluid in case but what do you guys think?
 
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