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What is the correct way to install a trans cooler

Jeepguy03

Jeepguy03

NAXJA Forum User
Location
Connecticut
What is the correct way to install a trans cooler in relation to flow? I have a B&M Supercooler on my XJ, but I don't have a temp gauge yet. From reading a couple threads on here, I think my trans cooler is installed wrong. Mine is a stacked plate cooler and is installed with the hose barbs facing down like shown below:

130-70264.jpg


My friend also has a 2000 XJ and we installed a flex-a-lite tube and fin cooler on his. How should this one be installed?

It looks like this:

400-4118.jPg


I just want to make sure I have the hoses routed correctly. I ran the hose from the tranny return line on the radiator to the cooler, then from the cooler back to the tranny on both Jeeps. I just want to make sure I have the coolers set up right. It seems as though the fluid should be going in the bottom barb and out the top according to some threads. Is this the same for stacked plate coolers and is mine installed sideways?

Thanks!
 
The location of the aux cooler in the lines has been beaten to death here before. Hasta
There are two common schools of thought here, the first is from the AW4 to the aux cooler, then radiator. The thought here is to make sure the tranny is given ATF at a consistant (preheated in winter) temperature.

The second is to leave the return line connnected to the radiator and interrupt the line back to the tranny for the aux cooler. I believe this is a paranoid attempt to get the ATF as cold as possible.

There is of course, option 3, run only the aux cooler.

When I installed my aux cooler, I deciced to go for the first option, since this is how the factory did it. I also don't like the idea of dumping freezing cold ATF back into the tranny in the middle of the winter. I monitor the temperature of the fluid leaving the AW4. After 5 minutes of warm-up it stays between 120*F and 140*F, unless I am in the mountains and not allowing the torque converter to lock up. Then it can get up to 180*F.

I don't have a high capacity cooler either. I am running the factory aux transmission cooler.

I see you live in Conneticut; Do you ever drive it in cold weather?

As for the physical mounting position of the cooler, I can't see where it would make any difference if the lines connect at the bottom. If the connections are at the side, logic would tell me you want the hot fluid entering the top connection, just like your radiator.
 
With most any sort of heat exchanger, it is hot at the top and cold at the bottom.

A cross flow usually sorts itself out and the hotter fluid floats to the top on it's own.

Something to think about if you divorce (bypass) the trans cooler in the radiator. Chances are you'll have shift issues (doesn't want to shift out of first or second gear) when the temperature gets down to around 0 F and it may not go away after the motor heats up. A little heat can be beneficial during a cold winter, oil gets thick.

I always install mine, in through the external tranny cooler, through the radiator trans cooler and back to the tranny. All of my XJ's are moderate duty, so I leave them hooked up that way winter and summer.
 
Sorry guys, I don't think I worded the original question correctly.

On both Jeeps, the trans coolers are installed after the radiator.

The fluid goes from the tranny to the heat exchanger in the radiator, through the cooler, and back to the tranny.

My question was about the orientation of the cooler in the front. I currently have my plate style cooler mounted with the fittings facing down. I read in one thread that the fittings should be horizontal and the input should be the bottom fitting, so it will fill the cooler from the bottom and get out any air.

Others seem to think it doesn't matter. Will it make a big difference? My cooler has been installed this way for about a year.

My friend has a tube and fin cooler on his XJ. The fittings on that one are mounted horizontally, but I have the input as the top fitting.

Just want to be sure both coolers are installed correctly for maximum efficiency.
 
My opinion is that in this application it doesn't matter which way the fittings face or which hose you attach to which fitting. The fluid flow through the hose is so fast that you can pump out 2 gallons of fluid in about 15 seconds (this is how I do my annual "poor-man's" tranny flush). With fluid moving that fast, you won't have air pockets.
 
NO.


face the barbs to the side or up.

for a stacked plate style, you will want the barbs to the side with the fluid entering the bottom and exiting the top.

if you have them facing down, you will trap air in the cooler and the fluid will cavitate.
 
Cavitate? Unlikely. It might aerate the fluid. Then if the fluid is aerated, it might cause the pump to cavitate.

rockclimber said:
NO.


face the barbs to the side or up.

for a stacked plate style, you will want the barbs to the side with the fluid entering the bottom and exiting the top.

if you have them facing down, you will trap air in the cooler and the fluid will cavitate.
Click to expand...
 
Wow.

ALL OEM external coolers are installed after the radiator.

It's pointless to install an air to air cooler before the radiator. You only bring the oil temp up to water temp at that point.

air won't get trapped in the cooler, no matter the direction of the ports. The pressure and volume of fluid passing through won' let that happen.
 
Glenn B said:
Cavitate? Unlikely. It might aerate the fluid. Then if the fluid is aerated, it might cause the pump to cavitate.
Click to expand...


HAHA! Schooled!!!


I have had the exact same tans cooler on my rig for going on 3 years now.

Fittings pointed down.

Daily driver, weekend warrior.

Hot California desert, cold California mountains.

ZERO PROBLEMS.
 
Gee whiz willickers--when you buy an AFTERMARKET PRODUCT, I recommend following the MANUFACTURERS instructions.

Every since Al Gorge invented the internet(s) you can access product information 24/7/365.
 
Can someone explain to me the term " torque converter to lock up"

I've been hearing it a lot lately and don't really understand it.

How and when does your torque converter 'lock up' and is this a good or bad thing? Is there a way to tell if it's 'locked up'?
 
A torque converter is a fluid drive coupling device. It's inherent design is to have slippage. A direct clutch is added inside to couple the slipping halves together, so when the clutch is activated, the halves turn together as a unit.. locking them together.

Hence the term torque converter lock-up

The locking action is desired as the slippage causes heat. You can see lock-up occur in the tachometer.. usually about a 200-300 rpm drop, and many times feels like an extra gear engaged.
 
Digger87xj said:
A torque converter is a fluid drive coupling device. It's inherent design is to have slippage. A direct clutch is added inside to couple the slipping halves together, so when the clutch is activated, the halves turn together as a unit.. locking them together.

Hence the term torque converter lock-up
Click to expand...

A 'direct clutch is added' as in aftermarket or is it always in there? I thought only autos had torque converters and standards just had clutches.

How can you activate the clutch in an auto and lock up the torque converter? Is it bad if you lock it up? What's the point?
 
here

http://en.wikipedia.org/wiki/Torque_converter


Although not strictly a part of classic torque converter design, many automotive converters include a lock-up clutch to improve cruising power transmission efficiency and reduce heat. The application of the clutch locks the turbine to the impeller, causing all power transmission to be mechanical, thus eliminating losses associated with fluid drive.
Click to expand...
 
Glenn B said:
Cavitate? Unlikely. It might aerate the fluid. Then if the fluid is aerated, it might cause the pump to cavitate.
Click to expand...

and that is different from what I said how?


Digger87xj said:
air won't get trapped in the cooler, no matter the direction of the ports. The pressure and volume of fluid passing through won' let that happen.
Click to expand...

false.

Original_MudButt said:
HAHA! Schooled!!!


I have had the exact same tans cooler on my rig for going on 3 years now.

Fittings pointed down.

Daily driver, weekend warrior.

Hot California desert, cold California mountains.

ZERO PROBLEMS.
Click to expand...

you're a dipshit.

nominated.
 
Digger87xj said:
Wow.

ALL OEM external coolers are installed after the radiator.

It's pointless to install an air to air cooler before the radiator. You only bring the oil temp up to water temp at that point.

air won't get trapped in the cooler, no matter the direction of the ports. The pressure and volume of fluid passing through won' let that happen.
Click to expand...
x2.

This is a ridiculous religious debate (cooler after vs cooler before) and I don't see why.

transmission_fluid_life_chart.gif


I don't buy the "it goes through the radiator to bring the trans up to temperature sooner!!!!!!!1" argument, either.

Kingkong0192 said:
Can someone explain to me the term " torque converter to lock up"

I've been hearing it a lot lately and don't really understand it.

How and when does your torque converter 'lock up' and is this a good or bad thing? Is there a way to tell if it's 'locked up'?
Click to expand...

Kingkong0192 said:
A 'direct clutch is added' as in aftermarket or is it always in there? I thought only autos had torque converters and standards just had clutches.

How can you activate the clutch in an auto and lock up the torque converter? Is it bad if you lock it up? What's the point?
Click to expand...


dude. JFGI.
 
Digger87xj said:
Wow.

ALL OEM external coolers are installed after the radiator.

It's pointless to install an air to air cooler before the radiator. You only bring the oil temp up to water temp at that point.

air won't get trapped in the cooler, no matter the direction of the ports. The pressure and volume of fluid passing through won' let that happen.
Click to expand...

I get where you are coming from and why, but! you are assuming the lowest possible temperature to the tranny is the only consideration.

If you put the, in air flow, heat exchanger before the radiator you are dumping some heat before the transmission fluid gets to the heat exchanger in the radiator. And since most, if not all XJ's, tend to overheat, putting the, in air flow, heat exchanger after the, in radiator, heat exchanger may not be the best solution.

Like most things automotive, transmissions are designed to have an optimum operating temperature. In many cases this is around 180 F plus or minus. On a typical day the coolant in the left side of the radiator is the coolest. On a really cold day the coolant on the left side of the radiator is the coldest and with the aux cooler after the radiator cooler, you may over cool the transmission fluid. Happens to me most every winter.

Your way is probably best for maximum transmission cooling, my observations are a little more inclusive and take into account where the excess heat goes (and into the radiator may be a poor choice on occasion) and what happens when the fluid is undercooled and gets thick.

Last observation, unless you mount the cooler below the transmission, you are going to be pushing air sometime in the flow cycle.:)

Mounting a cross flow aux tranny cooler to maximize getting as much air as possible out of the cooler makes sense. An air bleeder at the highest point in the system would make even more sense.
 
8Mud said:
I get where you are coming from and why, but! you are assuming the lowest possible temperature to the tranny is the only consideration.

If you put the, in air flow, heat exchanger before the radiator you are dumping some heat before the transmission fluid gets to the heat exchanger in the radiator. And since most, if not all XJ's, tend to overheat, putting the, in air flow, heat exchanger after the, in radiator, heat exchanger may not be the best solution.

Like most things automotive, transmissions are designed to have an optimum operating temperature. In many cases this is around 180 F plus or minus. On a typical day the coolant in the left side of the radiator is the coolest. On a really cold day the coolant on the left side of the radiator is the coldest and with the aux cooler after the radiator cooler, you may over cool the transmission fluid. Happens to me most every winter.

Your way is probably best for maximum transmission cooling, my observations are a little more inclusive and take into account where the excess heat goes (and into the radiator may be a poor choice on occasion) and what happens when the fluid is undercooled and gets thick.

Last observation, unless you mount the cooler below the transmission, you are going to be pushing air sometime in the flow cycle.:)

Mounting a cross flow aux tranny cooler to maximize getting as much air as possible out of the cooler makes sense. An air bleeder at the highest point in the system would make even more sense.
Click to expand...

If you are worried about the oil not getting up to temp, install a temp by-pass, or buy a cooler with one installed. Otherwise most driving conditions aside from the most extreme are not going to even be a factor for most people. If extreme cold IS and issue, again, install a temp by-pass.

Aside from Kastein, does anyone here even know where the fluid that is going through the trans cooler comes from and goes to?

Air in a cooler is NEVER going to cavitate the pump, cause cooling issues or cause aeration after the first time the torque converter locks up. It simply won't happen.
 
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