So I got a new tranny cooler cause the stock one just wasn't cutting it towing my trailer in the summer!! I shopped for quite a while and was going to get a Derale until I saw this one in another thread on here and thought I'd give it a try. (photo courtesy of dennisfranz) This isn't my truck but it's the same cooler and the same set up as my '02. I did a great looking install with Earl's braided line and all Earl's -6 fittings, minus the filter you see in this photo. I tried to get some good pictures but I never had my grille out as the truck in this photo does, so I really couldn't get any I liked. That's the only way to do a job like this. This cooler has a little more than double the cooling surface area of the stock 150 cooler!!!

The installation..literally took 30 minutes to install the cooler. A little longer for the lines and stuff to get them exactly as I wanted, but the cooler was a snap...should be, it's made for this truck. (Note...don't know why the grille is out of the truck in this photo as the grille does not have to be removed at all to install. The center hood latch piece does, but it's three bolts and gone!)

So does it do the job?? That's an understatement!! Best/favorite mod to my truck yet, and that's a helluva statement to make. Normal tranny temps reduced 35+ degrees!!! Not only that (not that 30* isn't extremely significant) but it's a lot harder to get the tranny hot like before. Example...I got stuck going up a hill behind a truck. I was in 2nd gear and the pace was right at that point where I just could not get my converter to lock up. I absolutely could not get my tranny above 210* That's up hill, 2nd gear, 3,000 rpm, converter unlocked, trailer in tow, and about 75* outside. That's a HUGE impact!!

So, my main question for this thread...How cool is too cool for tranny fluid??? With this cooler, it's gonna put my tranny temps during normal driving at about 50-55* over outside air temp. This winter, that'll be pretty dang cool and I've never heard anyone talk about keeping fluid too cool????

 

Sounds like a nice upgrade. Looks mint as well!

Aaron

 

there should be a cooler bypass valve for when the temp is to cool.....

Anyone know about the external filter shown? any downfalls to having the external filter? I HATE auto's.. and anything I can do to make mine last longer will be a plus to me.

 

Yep!! Just as suspected...first morning drive with the new cooler today. 40 miles to work and 60* outside. The needle on the gauge (starts at 120) never budged.

Another observation while changing my oil tonight. I placed a shop rag in front of the cooler with one of the fans running and the fan sucked the rag to the cooler. That's sucking air through a two row radiator, the A/C thingamabob, and the tranny cooler. The stock cooler in the stock location would never get any airflow over it during low speed driving like that!!!

 

Anything less than 100 is too cool.
I think you are safe. Might want to put some cardboard over it if it gets really cold.
Alan

 

Ya most good coolers will have a bypass for cold weather. If it gets to cold the tranny fluid doesnt flow as well which can cause problems, which is why they put in the bypasses.

 

Well, this bypass must be part of/internal to the tranny cause there aint one on this cooler, nor was there one on the stock cooler that came off. There's also only one line in and one line out...so fluid has to go throug it!

 

I hate the bypasses, I avoid using them. If I need them i'll go back to the radiator for fluid warming. All it takes is for them to stick or break a spring and you'll cook your trans.
Alan

 

And you'll find that your trans fluid gets colder.

I was a trans cooling engineer at Ford. I ran tests that showed that the radiator NEVER warmed the trans fluid. When it's cold out the radiator does such a good job of cooling the engine coolant that the water in the tank where the trans cooler is located rarely warmed above the outside temperature. When it did warm above outside temperature, the ATF was already MUCH warmer than the outside temperature. When the coolant in the bottom tank was warmed, it was because the ATF warmed it!

For these tests I had thermocouples in the coolant in and out of the radiator, in the ATF into and out of each cooler, in the trans pan, the test port, and several other places, too. I usually recorded data on 35-40 locations.

 

This I believe!!

This is still the first I've ever heard of a cooler bypass...unless you guys are tallking about an aftermarket one that's added in line somewhere. Even then, I've seen thermostats, but never seena bypass type product that works if it's too cold. Is this what you guys are talking about???

So now that we've got someone on here that really know's a thing or two about this, what kind of numbers have you seen?? As I mentioned, during constant highway driving my tranny is running about 55* over OAT. This winter, that'll put my fluid in the low 90's easily. dirtydog threw out 100*...is this a fluid thing or a tranny thing?? Maybe I'll send Amsoil an e-mail and see what they say.

 

Cold weather temperatures are hard to pin down. They are very dependant on the type of driving, the OAT, the vehicle, etc. 90F isn't going to hurt it, but it will cost some fuel economy. The trans was designed to run hotter than that and there will be more drag at the cold temperatures. You might want to consider a cold front, or at least some cardboard in the winter.

There are two types of bypasses. One will open if the pressure going to the cooler is too high. This can save the trans if the cooler plugs. The second type is a thermostat that will bypass the cooler until the ATF is up to temp.

 

The transmission temperature sensor with the factory tune will disable lockup and overdrive below 100 degrees.
Alan

 

Also - consider that there is a thermostatically controlled valve block in your lines coming form the tranny ( on 04+ 4R75E's I believe). This won't open until the fluid temp reaches approx 170 or so (could be wrong on exact set point, but it's up there).

Follow your lines and you'll see it.

Are you folks with aftermarket coolers removing these things?

 

There is a timer for max time to be in cold shift mode. The factory tune doesn't lock out overdrive and/or lockup based solely on temp.

Darrin

 

That is the bypass.

Darrin