I would like to install a tranny cooler and was wondering if one with a fan would be necessary? I've seen lots of guys use the kit from B&M (p#70268?) and was thinking of that, but I've seen they also make a cooler that comes with a fan, set to come on at 175*. I think I'd be ok out on the road, but I was thinking that on a slow moving trail, I might want one with a fan. I will also tow once in awhile.

 

I installed a Flexolite tranny cooler, 26000 GVW size. I mounted it in front of my radiator and condenser. Your stock electric fan mounts to the back of all 3, pulling air when the fan relay turns it on. My cooler completely fills up the grill openings, I can commute 50 miles home (high speed), get out and immediately put my hand on the cooler and not be burned. I've had no problems or issues with the stock fan doing the job, and my a/c and engine temperature has NOT been affected at all...

 

My concern was, when running a trail, theres little air flow, and your slipping the torque converter a lot, building up lots of heat. The factory fan is only set to come one when the a/c switches, or the coolant temp. sensor tells it too, it wont come on if the tranny is getting to hot, unless its set to do that from the factory.

 

[QUOTE=afoulk;600294]My concern was, when running a trail, theres little air flow, and your slipping the torque converter a lot, building up lots of heat. The factory fan is only set to come one when the a/c switches, or the coolant temp. sensor tells it too, it wont come on if the tranny is getting to hot, unless its set to do that from the factory.[/QUOTE]

The transmission temperature will turn the fan on.

 

Do you know what they are set to turn on at? And I take it I'd be ok with that B&M cooler without the fan then, correct? That seems to be what most guys are running.

 

I think the computer turns on the fan when the transmission temp reaches 230.
I also found this in the service manual:

P0218-HIGH TEMPERATURE OPERATION ACTIVATED
For a complete wiring diagram Refer to Section 8W.

Theory of Operation


The DTC is an informational code only and is being set to aid the technician in determining root cause of a customer driveability issue. The code is also intended to alert the technician to determine if a cooling system malfunction has occurred or if an additional transmission air to oil cooler should be added to the vehicle if the customer regularly drives in a manner that overheats the transmission.


When Monitored:
Whenever the engine is running.

Set Condition:
Immediately when an Overheat shift schedule is activated when the Transmission Oil Temperature reaches 115° C (240° F).



"3. HIGH TEMPERATURE OPERATION
--------------------------------------------------------------------------------

This DTC is an informational DTC designed to aid the Technician in diagnosing shift quality complaints.
This DTC indicates that the transmission has been operating in the "Overheat" shift schedule which may generate a customer complaint.
The customer driving patterns may indicate the need for an additional transmission oil cooler.
With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Check for any Service Information Tune-ups or Service Bulletins for any possible causes that may apply.

 

I dont' know, I think I'd want the fan to kick in before it gets that hot. Thats kinda scary actually.

 

The A/C will turn on the fan. I monitor the engine temp in stop and go traffic. Turning on the A/C keeps the engine temp to around 190 to 195. It would keep air going through the tranny cooler, too.
To answer your question in another thread about coolers with fan, I have seen pictures on here showing someone's cooler mounted under the Jeep. There was a fan on it to pull air through. A quick search was unsuccessful. Maybe someone here remembers where the thread is.

 

I personally think the best additional mod is a trans temp gauge. You can turn on your AC for a few minutes if you see the trans temp climbing off road (or otherwise). Installing the gauge in the console is much easier than installing a fan anyway.

With the big B&M cooler I almost never have trans temps over 180 degrees, even with off road use. I managed to make it to 200 degrees at the sand dunes after multiple consecutive hill climbs, but 1 minute with the AC on cooled it to under 180.

At this point if anything I am worried about trans temps that are too low. I can drive 100 miles in 60 degree temps and not see over 100 degrees on my gauge.

I also had issues fitting the cooler. Brackets in front, cooler behind just fits in the space behind the grill without further extensive modifications. It is tight enough that the brackets would not (easily) fit behind the cooler. It will be a real challenge to get an extra fan in there with the cooler.

 

I never took notice, doe the fan run all the time with the A/C on?