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It's really getting hot here in Vegas (116 yesterday). My trans temps are up around 200 much of the time. I hit 220 sometimes when I'm going slow. I think a lot of the problem is the fact that there's an A/C condenser, intercooler, and the radiator all trying to dump heat in the same place the trans cooler is. The engine temp seems to be pretty steady just over 200 so I'm most worried about the trans temps. BTW, my trans temp sender is in the line to the engine cooler so my temps should be the highest anywhere in the system.



I've been thinking of a couple options like putting in an extra trans cooler under the truck or maybe putting in some sort of water sprayer to cool off all the radiators when things get hot.



What does everyone think? Is it worth going to all this trouble or would I be just as well off to change my trans fluid more often or something like that?
 
Install a Manual Fan Switch. The Cummins 48re combo is complex, nothing the aftermarket is producing is equal to it,it is thermostatically controlled.
 
Will some one that has done this addition tell us where they mounted the cooler and how has it workedout for them. Any photos would be "cool" also.
 
I like the looks of that pro weld cooler. I'm going to do a little more research before I drop 650 bones on it but it looks good. I especially like the offroad protection. That was one of my main concerns with putting a cooler under the truck.



I'm curious about the manual fan switch too. I did a search for that and didn't find much. Does anybody have any more info on it? Is this just a simple mod that locks up the stock fan? I need to check but I would think my fan is running about all the time right now anyway.
 
This is Matt400 wiring diagram. It will not Upload, I will invert it in a different format, and Post it Tonight. It is the fan override switch. .
 
How hot does your transmission get?

If you don't have a transmission temp gauge you have no idea what going on. Alsa the temp gauge must be installed correct so you get a true reading. I just put a gauge on my 06 because this is the first automatic transmission I have had to pull with. I called Massdiesel and got the correct lines with port for temp pod. It works super not cheap though. Without the temp gauge you have no idea what going on with your transmission. :confused:
 
KennethS said:
I called Massdiesel and got the correct lines with port for temp pod. It works super not cheap though. Without the temp gauge you have no idea what going on with your transmission. :confused:



JamesHanna said:
BTW, my trans temp sender is in the line to the engine cooler so my temps should be the highest anywhere in the system.



He`s got one.
 
Manual overrider diagram,If you Hardwire as shown,Your engine will raise RPMs to 1000 intermediately,You temp gage will rise and your oil Pressure gage will drop. (When Engaged)
 
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TWest... Can you elaborate on the thermostatically controlled part of the 48RE?? I am not happy with the trans temps one bit on this truck. It is way too hot. It has been in the upper 90's low 100's here in TX since I bought the truck. It was running 185-190 down the highway empty before the Hy-Tec. It is now around 180. I towed the fifth wheel and it was around 195 most of the time and climbed to 225-230 in 30 minutes of stop and go Austin traffic. That is unacceptable to me. I have had three Fords which never went about 200... usually 165-170 with the same setup. The other two Dodge's I have had were sticks. I am about to order a cooler with fan control to add between the stock cooler and transmission to get the temps down. If there is a problem with a stock thermostat?? I would prefer to have that looked at first.
 
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TWest said:
Manual overrider diagram,If you Hardwire as shown,Your engine will raise RPMs to 1000 intermediately,You temp gage will rise and your oil Pressure gage will drop. (When Engaged)



How about DTC's ?



Bob
 
Their are Two Plate and Fin type Trans Cooler installed in all Cummins Dodge 3gen Automatics,One primary which is mounted on the Driver side and is water-oil cooled and act as a trans fluid warmer in cold Temps. One auxiliary mounted air-oil cooler located in the front of the Radiator and has a thermostat located at the upper right an acts as a Bypass when the when the fluid is 125* or less,When closed the fluid will bypass the Auxiliary cooler and return to the transmission,All fluid travels through the Primary Cooler. So adding a third cooler will not help Much,( We know this Because we have install additional coolers with little success). most have had much better success with adding the Fan override switch. The system Just Needs more air volume than the Stock Program allows, if you could load software to engaged the fan when the Trans fluid hits 160* I doubt you would ever see above 185*. It is a robust system that just needs earlier fan engagement. .
 
Bob4x4 said:
How about DTC's ?



Bob



As long as you Make the Resistance is less than 222*, 180ohm 218* no codes, 223 which is 195ohm will set a DTC. this is 03/04 ,04. 5 and up Higher ohms . I have not check 2006.



04. 5/05 same wiring 185 ohm (On Edit)
 
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TWest,

I would think that while travelling down the highway at 70mph the most air available would be present at that time. I am still seeing 195 while towing... not alarming, but would prefer 180. I would assume the fan is off at this time since it likely does not produce a cooling capacity greater than the airflow present at this speed. I am assuming the fan comes on at low speeds with little airflow... where I was reading 220 plus. Do you know what temp brings on the fan... perhaps mine is not coming on, or what temp routes the fluid through the second cooler versus sending it back to the transmission.



I am also assuming that adding an additional cooler before it gets back to the transmission will only cause the fluid to be bypassed away from the auxiliary cooler causing the fluid temp to remain the same... ie using the primary and the added cooler instead of the auxiliary to maintain what Dodge thinks is a good operating temp. The only way around this would be to make the added cooler larger than the capacity of the stock coolers combined... where the heck do you mount that!
 
Somthing to think about when adding a cooler is the following. If you put an additional cooler in series, the fluid becomes more restricted (due to additional line length) though the line, but additional length=more cooling potential. If you go parallel where your line spilts to feed two coolers and then re-unites, you get the same affect for cooling, but with no loss or restriction in performance. The fluid slows down by 1/2 as it seperates into each leg of the cooling circuits (if they are identical) and then resumes its speed when they reunite. This is how the rapid cool systems work and your radiator.



If I had an automatic, which I use too, I would build a parallel system when adding an additional cooler. Food for thought ;)
 
Is there a way to put a switch on the on the manual transmission, I would like that so when the truck is Idling I can cut the fan on?
 
TWest said:
Their are Two Plate and Fin type Trans Cooler installed in all Cummins Dodge 3gen Automatics,One primary which is mounted on the Driver side and is water-oil cooled and act as a trans fluid warmer in cold Temps. One auxiliary mounted air-oil cooler located in the front of the Radiator and has a thermostat located at the upper right an acts as a Bypass when the when the fluid is 125* or less,When closed the fluid will bypass the Auxiliary cooler and return to the transmission,All fluid travels through the Primary Cooler. So adding a third cooler will not help Much,( We know this Because we have install additional coolers with little success). most have had much better success with adding the Fan override switch. The system Just Needs more air volume than the Stock Program allows, if you could load software to engaged the fan when the Trans fluid hits 160* I doubt you would ever see above 185*. It is a robust system that just needs earlier fan engagement. .





So why not install an electric pusher fan in front. GM started doing this on the Escalades because the A/C would start blowing warm air when at a stop. Doing this would also not put added load on the motor.
 
CBrahs said:
So why not install an electric pusher fan in front. GM started doing this on the Escalades because the A/C would start blowing warm air when at a stop. Doing this would also not put added load on the motor.

Their is not enough room for Fan and Motor. Placement in the middle is about 1" short of any fan/motor I have seen.
 
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