The best cooler you can get is a cooler from a 6.0L.

 

Gotcha!! I understand how it works now.
However, I'm left with one question? Is it a valve that when triggered (I think by higher than normal line pressure), opens fully?
Or is it more of a regulated - pressure-based function....
ie; if the bypass sees a 50% increase in pressure (do to insufficient flow or a blockage) does the bypass system only funtion at 50%?

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I'm pricing out radiators by the way - I don't want to take the risk of allowing debris into the trans. Also, I think I'll replace the generic tube and fin aftermarket with a Tru-cool 40k.

 

You can take it out and have a radiator shop clean it, check for leaks and flow test the trans cooler lines in the radiator. I believe the spec is 1 gallon/minute. Anything less and you need to purchase a new radiator. My '99 F250 doesn't have the trans cooler lines in the radiator (bummer). In that truck, I am running the stock cooler plus a Tru Cool HD and it keeps the temps low while towing heavy. However, when I am backing up (such as when parking my 5th wheel in the side yard...), the temps do climb more than I'd like. If you tow heavy and find yourself in situations where you are driving very slowly (low air flow) or driving in reverse, then having the cooler lines in the radiator is a HUGE bonus. If you don't really tow that much, or very heavy... then you can get by with a good stacked plate cooler in addition to your stock trans cooler and you should be fine.

A tube and fin cooler could be restricting flow enough to cause your bypass to open. This would have the effect of raising your trans fluid temps.

The TruCool Max seems to be a good cooler. I am running one on my F450 and I have a pretty hard time getting the trans temps above 155 (ambient temps around 95 degrees, A/C on high, stop and go with hard accelerations). I believe 170 degrees is the ideal operating temp but I might not see that until the summer arrives and I am towing heavy. I will find out soon enough....summer is almost here.

EDIT: I had some time this week to use my scanner and look at the trans temp as measured by the internal OEM sensor and compared to my pillar mounted gauge (Art Carr brand...). It's kinda hard to check the gauge for accuracy since the needle has a very narrow sweep (about 100 degrees on face of the gauge). As near as I can tell, the trans temp reading via AE is about 8-10 degrees higher than what my pillar mounted gauge shows. The width of the needle on the analog gauge equates to about 10 degrees of temp on the scale so it's a guessing game as to what number the analog gauge is registering. As near as I can tell, while driving in city stop and go traffic with A/C blasting in 92 degree ambient temps....the analog gauge shows about 160 degrees while AE shows 168-170 degrees. Once I get on the highway, the analog gauge drops down to the 150 degree range while temps on the AE slowly drop to around 145-148 degrees and hold stead at that temp for as long as I am moving down the road. If I flip the switch on the analog gauge to measure the temp of the fluid in the pan (separate sensor) then the gauge drops another 10-12 degrees. My analog gauge has two sensors, one in the test port and the other in the pan. The temp in the pan usually runs about a needle's width cooler compared to the reading from the test port (10-12 degrees in temp).

In summary, on this particular truck. If AE is showing 168-170 degrees for trans temp then my pillar mounted analog gauge will normally show about 160 degrees at the test port and 145-150 degrees if looking at the sensor mounted in the pan. If I remember correctly, this was about the same variance observed on my '99 pickup truck with ISSPRO gauges. This leads me to conclude that fluid temps in the pan is about 20 degrees cooler than the temp inside the case (or wherever the OEM sensor is located).

 

So, if I'm going to order a Tru Cool unit, which one?

The 4739 cooler?
Or the 47391 - cooler w/o cold weather bypass?

I live just outside of Boston, and plow/operate frequently with temps below 32F.

....anybody hate me yet?? hahaa

 

I replaced my radiator when my trans went out. A new radiator from Performance radiator is 230.00 in Hawaii so it should be cheaper in the states. It's only a 2 core but its all aluminum and is more efficient according to them but i haven't any cooling issue so far.

 

Id go with the bigger 6.0 cooler if your plowing. The plow blocks airflow while your driving around and when your plowing your operating the truck at low speeds, shifting in and out of reverse, pushing snow and it all adds up to more heat. I don't know what the tru cools cost and don't remember what my 6.0 cooler cost but it will offer more cooling capacity and is defiantly the better option.

 

Get the 32 row cooler for or from a 6.0 i installed mine 2 years ago and love it. We get super hot here in FL 100* days and 98% humidity i run below 200* towing all summer. Normal driving 150*. I know a guy who owns a tranny shop in town he did the entire tranny in a 6.0 and installed a new cooler. I got the old one and it was in mint shape. Got it for FREE No leaks no high temps. I would suggest checking some tranny shops in your area and see if they might have one layin around. Just a thought

 

i got a 2002 f350 4x4, i noticed on my scangauge 2 that just driving maybe 50 miles that if my engine oil temp is 200 and the coolant at 180 the tranny is also 180 thats just general driving my 250 hardly ever gets to 160 i wonder if im in the same boat as you, my worry is this is the original tranny at 310,000 miles

 

Do you see something wrong with those temperatures? I don't. Seems normal to me.

 

Thats good to know, keeping the tranny under 200 is basically the way to go? Does it matter at what temp the tranny is to turn off the truck?

 

Don't turn it off when the temp is above 220F. Let it idle or fast idle in park or neutral.

 

I remember calling on Mark for my concerns I thought were to high trans temp (190-200*) and he told me the same thing, nothing wrong there. He said the concern would be hitting 220-230 constant or above if I remember correctly. Are the derale coolers considered a tube and fin because I got one on mine now, never had any issues with it, great cooler IMO.

 

It's not what they are considered, it is what they are or are not.

A tube and fin has one tube that passes back and forth with fins to dissipate heat. A stacked plate cooler has a tube on each side of the cooler with many passages between the two tubes. Which one describes the Derale cooler? I haven't seen one to know.

 

They make both but most of the units you see sold on the internet are the tube and fin style from what I have seen.

 

Alright, my 40k cooler came in today - I removed my generic "auto-parts store cooler" and replaced it with the Tru-cool unit.

While doing this, I examined the transmission's cooling system a bit - The lines run from the trans - directly to the aftermarket cooler, and that's it. The stock (lower) cooler has been disconnected, as well as the radiator cooler. I'm going to replace the radiator before summer hits - in order to get my cooler hooked up.

But, after replacing the tube and fin unit with the Tru Cool 40k (stacked plate), I've noticed a 40* drop in trans temp on the street, and a 50* drop at highway speed!

Here's the old one:


And the new one: