One thing you DON'T want to do is eliminate the rad cooler portion of the trans cooling system because it warms the trans when it's cold out.

 

See now this is one thing I am confused about.
I know from experience that first thing on a cold morning my Jeep will shift a little funny from first to second.
After being on the road for 5 minutes, if that long, it is fine.
So I understand what you are saying.
But with a factory tranny cooler, which I have intentions of putting in some day (just because), the return line goes from the radiator, to the tranny cooler, to the tranny.
Lots of guys take the radiator out of the equation completely when hooking up aftermarket ones.
Isn't that kind of working against each other. I mean Jeep did it from the factory.

 

I've HEARD that the in rad exchanger helps smooth temp spikes that the trans would normally see with just a cooler. During the winter time you can use a piece of cardboard behind the grille or one of those grille tarps like on an 18 wheeler to restrict airflow though the coolers.

 

I'm trying to determine if putting one of these in is really worth the effort and money. I mean is it just a few degrees difference or is it pretty significant?

I've decided to change out the radiator and hoses first. with that crap in it from the PO... I think I'd rather make sure the main cooling system is completely up to snuff.... it works fine here with no leaks....but going to a much warmer climate and much, much heavier traffic conditions... who knows how long that patch will continue to last. Then if it makes sense, add a trans cooler after that.

 

"Then if it makes sense, add a trans cooler after that."

Sounds like a plan. I added mine as a precaution for when I would be towing a loaded utility trailer on and off road.

 

Yeah... I think that is going to be the best route... gonna order that one today...and then order a trans cooler at the same time.

Not sure about an oil cooler yet...but I've heard from other XJ owners that especially with the auto trans we have... it can really help lengthen the life span of them. So moving somewhere hot or not... sounds like cheap insurance to me.

 

All this trans cooler talk makes me happy my XJs are both sticks.

I daily drove my 99 as my only car for about a year in Miami. I worked in an office and regularly saw stand-still traffic. It did fine rubbing elbows with Mercs, BMWs, Ferrari's, etc. etc.

 

Most (almost all) of the heat created in an automatic transmission is from the churning fluid in the torque converter. In a stalled condition, that is engine running and stopped in gear, all that energy made by the engine doing nothing is turned into heat. I'm pretty sure 250*F is the limit to where the fluid begins to break down and oxidize. All this heat being run thru the rad cooler adds to the rad's cooling load and makes an overheat more probable. This is just Physics. I think the best trans cooling system would have a thermostatic valve to send fluid thru the aux cooler only when a certain set high temp is reached and shut off the rad portion of the trans cooler when this set point is reached. I said the best, not the most inexpensive.

 

Any specifics on what that one would be?

 

Do you know if the B & M trans cooler bypasses anything of the OEM routing to the radiator? Or where it splices in?
I'm seriously thinking of doing both the radiator and the cooler at the same time. If I can do this without making too much of a mess I can do it where I'm at now....if not I have to have a shop do it which would suck because they are both very easy straight forward jobs that if I was back in a house I could do in my driveway. I'm only renting right now because of my impending move out of state.

 

It's spliced in line with trans return line after it leaves the radiator cooler. It bypasses nothing associated with the OEM one. In fact in monitors resistance to flow by allowing a controlled amount of ATF to pass through a self-regulating orifice. Controlled by viscosity, thicker ATF is returned directly to lube through two bypass openings in the stacked plate core, while thinner ATF is directed through the core to cool as operating temperatures increase.

 

As far as which direction the fittings go up,down,or on the sides I don't know about other brands but it doesn't matter with the B&M cooler. Mine hook up at the bottom of the cooler. This was posted in 2014:

"B&M coolers are made by LONG Mfg. which also makes Tru-Cool stacked plate coolers. Per the FAQ at the True-Cool web site, the stacked plate cooler inlet/outlet can be mounted up, down, sideways....makes no difference.

We installed a B&M #70264 cooler and I called B&M about the inlet/oulet mount direction......the B&M engineer said disregard the instructions that came with the cooler and mount however I wanted....up/down/sideways. The B&M cooler has "LONG" plainly stamped on the mounting flange.

B&M says for max efficiency, mount their auxiliary cooler inline with and after the factory cooler. If u r going to bypass the OE factory rad cooler, I would strongly recommend installing a tranny fluid temp gauge with the temp sender mounted in the forward/hot line and as close as possible to the fitting on the side of the tranny.

FAQs at the True-Cool website:
How should I mount the oil cooler fittings?
Fittings can be located up, down or sideways. This advantage, plus their compact design, make installation of our coolers quick and easy."

 

Thanks for the diagram...but it seems a little confusing to me if I'm looking at the directional flow correctly.
Doesn't the fluid make one large loop from trans, to cooler, to the radiator, then back to the trans? Or am I missing something?
Be kind... I've done a lot of work on vehicles before, but never installed one of these trans coolers before.

 

"Doesn't the fluid make one large loop from trans, to cooler, to the radiator, then back to the trans?"
You almost got it. Fluid loops from the trans to the rad cooler to the aftermarket cooler and back to the trans. (I have NO IDEA why this is red!)


So the install is out of the trans (front line which doesn't get altered) and into the radiator cooler (top or bottom depending how yours set up). Out of the radiator cooler (you'll splice into this line that comes from the top or bottom line depending on how yours set up) into the aftermarket cooler. Out of the aftermarket cooler (connect to the other end of the line you spliced) and back to the trans (rear line/return line).

 

Gracias mi amigo