2002 jeep grand cherokee transmission cooler lines diagram

Hello All,

I recently decided it would be a good idea to replace my leaking radiator myself, after lots of cuss words, broken knuckles and broken metal transmission lines, and 2 hours of my life I'll never get back.. it came out.. Now, I went ahead and bought new lines (pictured)

But, I can't for the life of me figure out which rubber hose to plug the top vs bottom in. Does it matter? Thanks!

I can't see any reason why it would matter. It should flow freely in either direction.

According to Chrysler it does matter... I couldn't find the drawing showing the flow pattern for the hoses. Maybe someone else could. However as with all heat exchangers contrary to "gravity effect thinking" you feed them from the bottom to prevent air in the system so the Feed line from the front of the trans is connected to the bottom of the Rad and the Return on the rear of trans is connected to the top of the Rad. If you imagine flow from the bottom up will always keep the Rad chamber full facilitating the best heat transfer and also will not allow air bubbles to form from a gravity drop.

In any event regardless of whatever any drawing shows this is the best way from a Heat Transfer & Flow Mechanics viewpoint. However I'm pretty sure that the Haynes Manual (I think or is it the Chrysler Drawing) confirms this. I would like to c the drawing to confirm the front line is feed etc...

Thanks for that Drew, I figure worst case scenario I can hook it up, and since I have to make an appointment at the dealership to get my tow hitch / gas tank protector installed anyway, I can ask them to double check it there.

Maybe this will help?

Looks like top or upper line from transmission to lower radiator fitting, then bottom or lower line from transmission to upper radiator fitting. (Ignoring the aux cooler assuming you do not have one)

I got rid of the radiator-integrated setup and added an external to the front of the radiator. I always thought the decision to run it through the radiator was from someone on acid.
Imagine this conversation...
"We've got to cool down this hot transmission fluid ...so let's run it over to where that radiator fluid is that's already good and hot."
"We will run the trans cooler line up through the side tank of the radiator where it gets less airflow than the middle of the radiator. That should be plenty effective to give the trans fluid plenty of life and dependability."

I believe the reason its run through the radiator is to help bring transmission fluid temps up faster from cold--I could be mistaken however.

I believe that is correct. I installed an aftermarket transmission cooler but still use the radiator cooler as well. I run it in this orientation:

Transmission --> Aux Cooler --> Radiator Cooler --> Transmission

This way, I'll cool the transmission fluid plenty but when it's really cold out, I won't risk over cooling the fluid.

I believe the reason its run through the radiator is to help bring transmission fluid temps up faster from cold--I could be mistaken however.

U r not mistaken. Plumbing it this way also provides more of a consistent Trans fluid temperature.

I'll concede that it was probably the reason as opposed to an acid trip then.
In the hot South, I'll keep the fluid out of the radiator and let it warm up plenty on sub-freezing temp days.
In reality though...isn't heat more a cause of death of a transmission before cold is?

Maybe this will help?

View attachment 1926305

Looks like top or upper line from transmission to lower radiator fitting, then bottom or lower line from transmission to upper radiator fitting. (Ignoring the aux cooler assuming you do not have one)

Thanks, that's for the V8, but hopefully it translates over to the 4.0

I got rid of the radiator-integrated setup and added an external to the front of the radiator. I always thought the decision to run it through the radiator was from someone on acid.
Imagine this conversation...
"We've got to cool down this hot transmission fluid ...so let's run it over to where that radiator fluid is that's already good and hot."
"We will run the trans cooler line up through the side tank of the radiator where it gets less airflow than the middle of the radiator. That should be plenty effective to give the trans fluid plenty of life and dependability."

I know this is old.....
I'm wondering if you've had to replace your radiator since adding the external cooler to the transmission? If so, were you able to use the radiator for manual transmission, which is I believe $100 less than the rad for auto trans (it is for the TJ anyway)..

All of those factory manual transmission WJs?

I know this is old.....
I'm wondering if you've had to replace your radiator since adding the external cooler to the transmission? If so, were you able to use the radiator for manual transmission, which is I believe $100 less than the rad for auto trans (it is for the TJ anyway)..

As IOC indicates the question is moot as there are no manual WJs.
I have swapped my radiator since adding the external trans cooler and there was no option other than the OEM integrated unit design available.

Well I'm red faced - didn't remember that WJ's don't have both transmission options, I'm in a TJ were the OEM radiator is considerably more for automatic over manual because of the internal cooler.

Sorry to awaken this thread, but it has some good info and a good diagram for seeing components on the first page.

I want to add a tranny cooler setup and want it to run through the Transmission --> Aux Cooler --> Radiator Cooler --> Transmission... like Chris

View attachment 1926305

I just found this thread https://www.jeepforum.com/forum/f13/...bottom-437914/

For the 45RFE transmission in the 4.7;
Top= output (Feed)
Bottom= input (Return)

Which would make the above diagram from PirateB the incorrect flow (if you have a larger than stock Trans cooler).

Since I am getting a pretty large trans cooler, I'm going to do might after the radiator for the same reasons mentioned previously in this thread.

I believe the lower trans line is the feed line. The upper is the return. You can always check by popping one loose and seeing if fluid comes out. Just be prepared for a bunch to shoot out. I recommend someone assisting by turning it on/off quickly.

If I'm correct on the feed and returns, I ran mine:

Trans Feed (bottom) -> Bottom of Aux
Top of Aux -> Factory Cooler where you unplugged the Trans Feed line
Factory Cooler return line -> Trans Return (top)

Here's a link with more information: https://www.jeepforum.com/forum/f19...uild-thread-1290252/index17.html#post15739293

:tea:

which does it connect to. I also need this answer