The trans typically runs around 30 degrees cooler than the engine in normal operation with the converter locked, acting as a heat sink for the engine with a properly functioning exchanger. Ideally, heat from both the engine and trans are being shed through both the radiator and the trans cooler via the shared path through the exchanger.

 

That sounds an awful lot like your agreeing with me while trying to make it sound like your not agreeing with me.

 

OK, I'll go along with that.

The idea is they work in tandem, with whichever part of the system is cooler drawing heat from the other. You remove the exchanger from the equation and they are on their own, cooling-wise. There are cases where an automatic trans will get much hotter than the engine, especially if the driver doesn't know how to operate the vehicle towing. But normally it's the engine getting help from the trans, coolingwise.

Clear as mud, now?

This is the part I might not agree with:
The exchanger is mounted down in the driver's side of the engine block water jacket, so the water it sees is closer to engine temp than radiator temp except as you say in a steady state WFO condition, i.e. max capacity, in which case it is always going to be hotter than the radiator.

 

Well everything seems to be working fine after re routing just washing out radiator with some cascade then im ready so again thanks for your help Nadirpoint

 

Hello
Are there any more lines other than in the front and out the back? Hard to see from where I'm sitting. Thanks.

 

Yeah, there's no way I'd tow anything with the heat exchanger bypassed. That is your main source of transmission cooling. The little toy cooler up front that Dodge gave you will not be adequate for much more than daily driving in cold weather.

 

The trans heat exchanger is for supplemental engine cooling and WARMING the transmission in cold weather. The air-to-air cooler in front of the radiator is the primary transmission cooling device.

 

Not exactly...

The exchanger is the primary cooler, quickly cooling the sometimes astronomical temperatures exiting the converter down to coolant temp. Then the cooler up front knocks a few more degrees off on its way back to lubricate the gear train and then ultimately end up back in the pan. The "air-to-air" (oil-to-air) cooler that Dodge used is certainly nothing to write home about from an efficiency standpoint.

I suppose their would be some warming effect if the engine coolant warms up faster than the tranny fluid, but that certainly isn't the designed intent. The transmission makes plenty of heat on its own.

 

Define "astronomical." Mine runs around 150-160. Short-tripping in-town or off-road are about the only scenarios they generate much heat. The converter is normally locked cruising in 3rd or 4th, running like I said, around 150-160 generating minimal heat.
It has plenty of capacity in a 3rd Gen and is the thermostatically-controlled primary trans cooler. The t-stat is closed less than it is open normally, except as described above.
You suppose correct, but are certainly wrong on the intent.
In the specific situations I described above that is true. They represent a very small percentage of the real world normal use cases. Drivers who don't know how to operate the vehicle towing also will cause some issues themselves, but that is a different topic.

The system is designed and functions as I described.

 

Indicated transmission temperature depends entirely upon where the temp sender is placed. Most people put them in places that are of little use for accurate temp readings.

If cruising in 3rd or 4th gear with the converter locked was all anyone did, then we wouldn't have to worry too much about heat, would we. But, that's not all a transmission has to do. You will generally see the highest torque converter exit temps during low speed, heavy load maneuvers. It's not uncommon when running up against the converter (full stall) to see 260-270 degrees coming out of the converter and entering the exchanger, where it gets quickly cooled back down to coolant temp.

That's what the heat exchanger is for. It's a very effective fluid-to-fluid cooler. It's not to warm up the fluid. I can think of exactly zero reasons to take cool fluid from the pan, heat it up, and then try to cool it back down again.

But, then again, who am I...and what do I know?