Is this transmission cooling setup normal/acceptable

[El Tigre]

Before using any rubber type cap. I'd install an appropriate size pipe plug coated w/RTV. Or,at the very least a rubber stopper,then the cap.

 

[96-2D-Hoe]

It has a nipple on the open connection and RTV is not necessary.

 

[El Tigre]

And,when the cap fails? What then?

 

[HotWheelsBurban]

Same here - I have the same bypased saddle cooler on my C2500 - and no obvious explanation why it was done (coolant isn't leaking across it and while I haven't absolutely proven it doesn't leak externally, a rudimentary check showed no sign of it).

My concern is that I'm losing the pre-warming of the ATF (though coolant rad is cold until thermostat opens) and cooling (though how much cooling there is given quite high coolant temps is debatable). I live in a coldish climate so the pre-warming is more of a concern.

One difference I noticed is that your saddle cooler seems to have different fittings to mine. Mine are threaded (female NPT(?)).
There is another forum member who by-passed their saddle cooler as it was leaking. They aren't too worried about it!

If the truck has a recently replaced radiator, it may have done what my recently acquired pickup has done. The internal transmission fluid pre heater/ cooler has been leaking ATF into the coolant. Made chocolate milk just like it does with motor oil. No telling how long it's been doing this. I've had it 3 weeks, and last week it started shifting funny, so I checked the transmission fluid. None on the stick, and no obvious leaking underneath. Around the same time, it peed orange on the ground; the clamp on the filler tank bottle hose was old and letting it seep. Fixing that yesterday led to the discovery where 3 quarts of MERCON V fluid went! So now I get to spend $350 on a radiator and hoses and more coolant and a transmission filter kit and fluid.....

 

[El Tigre]

The problem is that when vehicle is shut off the coolant is still under pressure,and trans fluid is not. Unclear how trans fluid could leak into the coolant,without coolant also contaminating transmission fluid. Coolant will destroy a trans in short order if not aggressively mitigated.

 

[Pinger]

If the truck has a recently replaced radiator, it may have done what my recently acquired pickup has done. The internal transmission fluid pre heater/ cooler has been leaking ATF into the coolant. Made chocolate milk just like it does with motor oil. No telling how long it's been doing this. I've had it 3 weeks, and last week it started shifting funny, so I checked the transmission fluid. None on the stick, and no obvious leaking underneath. Around the same time, it peed orange on the ground; the clamp on the filler tank bottle hose was old and letting it seep. Fixing that yesterday led to the discovery where 3 quarts of MERCON V fluid went! So now I get to spend $350 on a radiator and hoses and more coolant and a transmission filter kit and fluid.....

That was a dose of bad luck for you on your Ford.
What happened to you was my first thought as to why my saddle cooler was bypassed when I found it had been (not least as this is a well documented failing of some Valeo radiators on some Mercedes-Benzs) but mine doesn't leak coolant (and ATF side isn't sealed off either). Maybe preemptively in case it happened but that's just a guess.

Currently tempted to fit a thermostat and have only the external (tube) cooler. It running cold is as much a concern here as hot - especially with winter approaching. On my mind is that I'd have to cut hard lines to fit a 'stat close to the gearbox and the swarf danger isn't to my liking. Maybe closer to the cooler where the flexible lines are. As you can guess, no final decision reached yet!

 

[Trlrider]

First, the rubber capped outlet on the radiator is for the HEATER, not used on many models.
The trans cooler fittings are the two below with the brass plugs.

I have had street and performance transmissions built by some of the best in the country and every single one suggest (highly) that the cooler in the radiator be bypassed and a efficient external cooler be installed.
The only time I have had a failure is when I left the internal radiator cooler inline for the supposed pre-heat on a truck that was built to live mostly at higher altitudes in the mountains.

What I see in picture a $20.00 e-bay/amazon cooler that is very inefficient and actually causes restriction.
The inline filter should be on the inlet to the cooler, and not the outlet. The purpose of a inline is to try and save the cooler from contamination in the case of a failure.

You say there is a temp sensor in the line, but where/how does the electric fan energize? Is there a seperate temp switch inline, does it come on with key on, or manually activated at the dash?

I have run Hayden Transmission coolers in street and high performance vehicles for years without added fan and rarely see transfluid temps over 190 degrees. Study a Hayden Cooler design compared to the one on your unit and you will see why they are more efficient.
I even use them on vehicles with hydra-boost setups!

Also if you are getting that high a temps, you may want to have your transmission checked by a professional as you may have something slipping internally! Improper converter lock-up possibly?

 

[BhutJolokia]

First, the rubber capped outlet on the radiator is for the HEATER, not used on many models.
The trans cooler fittings are the two below with the brass plugs.

I have had street and performance transmissions built by some of the best in the country and every single one suggest (highly) that the cooler in the radiator be bypassed and a efficient external cooler be installed.
The only time I have had a failure is when I left the internal radiator cooler inline for the supposed pre-heat on a truck that was built to live mostly at higher altitudes in the mountains.

What I see in picture a $20.00 e-bay/amazon cooler that is very inefficient and actually causes restriction.
The inline filter should be on the inlet to the cooler, and not the outlet. The purpose of a inline is to try and save the cooler from contamination in the case of a failure.

You say there is a temp sensor in the line, but where/how does the electric fan energize? Is there a seperate temp switch inline, does it come on with key on, or manually activated at the dash?

I have run Hayden Transmission coolers in street and high performance vehicles for years without added fan and rarely see transfluid temps over 190 degrees. Study a Hayden Cooler design compared to the one on your unit and you will see why they are more efficient.
I even use them on vehicles with hydra-boost setups!

Also if you are getting that high a temps, you may want to have your transmission checked by a professional as you may have something slipping internally! Improper converter lock-up possibly?

This is helpful, thank you. I am in Idaho so the truck will be operated in very cold temperatures at times, so I will need the pre-warming from the radiator before too long. The fan has a switch in the cabin and I don’t use it much. Was wondering about the quality of the cooler also, I will plan on tackling this real soon here and getting a bigger, better quality cooler on there along with the lines to the radiator. This is helpful, thank you. I am in Idaho so the truck will be operated in very cold temperatures at times, so I will need the pre-warming from the radiator before too long.

The fan has a switch in the cabin and I don’t use it much. Was wondering about the quality of the cooler also, I will plan on tackling this real soon here and getting a bigger, better quality cooler on there along with the lines to the radiator.

As far as the high temperatures, I have only seen those on 90+ degree days for very short periods, I have gone back to those same grades on cooler days and not had a problem but obviously it does get hot here. This last time out I dropped it into third to lock the torque converter on a 90° day and it didn’t get over 190. I have not felt any slipping.

 

[Pinger]

How much pre-warming is there really though?
The coolant radiator doesn't see heat until the engine is warm enough for its thermostat to open. Meanwhile the ATF has been taken from the warming environs of its gearbox and circulated out in the cold and returned colder than when it left (especially if there is an additional tube/fin cooler).
Is there a definitive view on the efficacy of this supposed pre-warming?

 

[HotWheelsBurban]

How much pre-warming is there really though?
The coolant radiator doesn't see heat until the engine is warm enough for its thermostat to open. Meanwhile the ATF has been taken from the warming environs of its gearbox and circulated out in the cold and returned colder than when it left (especially if there is an additional tube/fin cooler).
Is there a definitive view on the efficacy of this supposed pre-warming?

Yes I've wondered about this too. Guess part of it depends on how cold it is.