The radiator cooler was added mid year 2000. There has never been a way to heat the transmission fluid. The radiator cooler does not heat the ATF.

Not in my experience. Coolant temperature always has risen quicker. It's cooling an area heated by combustion. That gets a lot hotter than anything in a transmission ever gets. I've run vehicles from +121°F to -48°F and I have never seen a transmission warm up faster than an engine.

The cold side of the radiator can be anywhere from 15°F to more than 150°F degrees cooler than the coolant coming out of the thermostat. If the truck is running unloaded in a below zero ambient temperature the cold side of the radiator, where the trans cooler is located, is just about ambient. So the ATF cooler is seeing coolant around it that is at -40°F. How would that warm the ATF? It's still cooling the ATF.

 

Gotcha, sorry if I added confusion to the thread. I was under the impression its purpose was to help get the fluid up to temp when its real cold outside. I understand that the overall purpose of the entire system is to keep temps DOWN, but as with helicopters I assumed you also need to warm fluid in order to keep the pressures in check as well.

 

The trans should be warmed, but there is no system in th truck to do it, other than driving it. Working the trans will warm it.

 

Mark,

What's an "ideal" temperature operating range?

If towing heavy, should the trans ideally be allowed to come up to some temperature?

Pop

 

I was basing my obeservation on EOT, since I don't have a coolant temp gauge. If I had one, I'm sure I would see the results you are stating. I was thinking that my EOT was close to the ECT the engine was seeing. I realize EOT takes longer to rise than ECT. I just thought it wasn't that big of a difference in this case. My bad.

 

170°F is ideal.

Also 170°F. Usually when towing heavy it will get hotter than that, but 170°F would be ideal.

 

Good to know!

Thanks, Mark!

Pop

 

like Mark posted already,the ideal temp is 170 (iv read 175,but hardly worth a debate lol) degree's.
the answer to your question is yes.just like the engine,the auto trans has a minimum ideal operating temp as well.this temp is 150 degree's.
below 150 degree's and the efficiency of the trans suffers.this is a large reason for reduced fuel economy in winter months.
you can add an external oil cooler t-stat bypass yourself,fairly economically.i did this with mine,and it really helps getting the temps up quicker.

Transmission Oil


https://www.ford-trucks.com/forums/7...l#post10773358

 

Do these numbers hold true for full synthetic ATF, as well?

 

i would guess; yes.

im sure an auto trans works best at its minimum temp of 150 (preferably 175) regardless of oil type.but as we know synthetics flow soooooo much easier than dino juice when cold.
if i ran synthetic trans fluid (i did debate it) i personally would still try to achieve ideal trans temps (partly why i didn't go synthetic.)
however the advantage is,that while getting up to temps,the efficiency of the trans should still be decent.


as far as heat goes,check the flash point,it's likely also much better than dino,
again though,the clutch material in the trans etc.is only designed for so much heat.so again,if i ran synthetic in the trans,id still aim for the ideal 175F.
perhaps someone knows otherwise,but i wouldn't blindly run my trans higher in temps simply because the oil could take it.id still be concerned with the rest of the trans.
so in short,unless someone knows otherwise.id stick with the same chart myself if i ran synthetic oil.

 

While I can surely understand the effects of excessive heat on an automatic transmission and the validity of running an ideal operating temperature, what ill effects come with overcooling the fluid? You say "reduced efficiency". Can you explain this further? Are you referring to viscocity and flow characteristics of the fluid? I run full synthetic ATF with friction materials and trans mods that are not stock. My trans temps run in the 120-140* range, as measured by the TFT sensor, in the colder months and ~160* in the summer heat.

 

Good info! Since the 6.0 transmission cooler is such a popular mod I'm surprised this isn't a common mod to complement the cooler upgrade. In the winter I usually don't see over 130 degrees. Sounds like another item to put on the to do list.

 

In winter months driving empty which is what I usually do, from what Im reading and correct me if Im wrong I should still be trying to get my trans up to 170-175 degrees? That does not coexist with the 100 degrees above ambient temp at all guide lines that Ive read so much about over the past couple years, could someone explain, please because how Im taking this information is that even at lets say, 15 degrees outside air temp I stil want my trans to get up to 170-175 as much as possible.
During the winter months my trans guage usually doesnt move and it goes as low as 100 degrees.

 

the radiator section for the trans was added in 2000? what do you mean by this? this has been the factory way to cool a trans for years prior to 2000.
id like to know what this is.
at any rate,the radiators section for the auto cooler,does in fact raise trans temps.
have you ever run your engine a little on the warm side with an auto trans? if you have,you'll notice the trans temp also increase (even without extra load.let's say with a failing water pump/coolant fan for example.)
the coolant flowing though the radiator is very warm of course (around 200F for diesels,we'll say roughly.) this heat of the rad does indeed transfer over to the ATF fluid.im surprised to hear you say otherwise really.
clearly im misunderstanding this cooler type that was added in 2000,and im interested to learn more about it.

ideal transmission temp is 175F.this fact never alters due to outside temps.this is the main point of everything really.

the saying that you can expect to see such and such a temp depending on the outside temp is true.but this doesn't mean we can't increase the efficiency either via;
a.electric fan on the cooler (to help keep around 175 for all towing conditions)
b.adding a t-sat to help bring temps to the ideal trans operating temp when running empty/winter months.


right.the transmission fluids are rated and made to flow and work for a certain temp.
synthetics of course will be much more efficient over a wider range of temps than dino oil.your likely setup pretty good with the synthetic,but blocking off your external cooler during winter months (when empty) to try and maintain 175 couldn't hurt either.i personally would still add an external t-stat.simply because they're pretty affordable,easy to install,and having a temp year round closer to 175F is never a bad thing.


sadly,because most people forget (or don't even know) that all mechanical devices have a minimum/ideal/high temp range.due to auto trans being able to die literally inside a mile due to extreme high temps,the focus is always on keeping the "too high" temps at bay,and the ideal,normal operating temp got lost.
one would think running ATF at thicker viscosity (too low of temps) where the fluid is not designed to work ideally,wouldn't be the healthiest practice for the trans either ya know?

 

I thought our transmissions had a thermostat. It is a bypass that goes between the inlet and the outlet I think.

On my truck it came without the Oil to Water cooler in the radiator. The transmission overheated and was replaced under warrantee. When they replaced the trans they also replaced the radiator with the new style. I think that Ford realised they had made a mistake by eliminating the raditor cooler on the early 99's.