Last week towing my TT up a steep section on the way to Mt. Lassen, the tranny temp got up to 211 degrees. Now, from searching all the related posting, I know that the consensus is that 220 for extended time is probably the limit. But I do feel that if the grade was longer the temps most likely would have reached the 220 mark, and maybe beyond. My concern is that I do expect to be towing in near 100 degree temps various times up steep grades during the summer and may not always be able pull over. So, I’m considering upgrading the tranny fluid cooler, but have a concern. Even if I replace the cooler with a larger one, seems to me that the oil lines between the tranny and the cooler would be the limiting factor. In other words, if the heat buildup is faster than the oils can circulate and be cooled through the larger oil cooler, (due to the I.D. of the cooling lines), the whole thing will not be much more effective than with the stock cooler. Anybody upgraded their 2004-2008 cooler? Was it affective? Would I just be wasting my money? Truck is a 2004 F150 5.4, 3.73, tow package. From what I’ve read, the 2004 + have bigger coolers than the earlier models but does it have enough cooling capacity for high ambient temperatures up long grades? Since towing uphill reduces the speed, thus reducing airflow, I would think the temperature rise would not reach equilibrium. OK maybe too many variables to get any definite answers and everyone’s towing environment is different. But, controlling tranny heat must be doable though. I saw some real big fivers be pulled by ¾ ton diesels up the same grades, same ambient temperature. That’s got to generate some serious transmission fluid heat.

 

The larger tranny coolers reduce the fluid temp more than a smaller cooler thereby reducing the trans temps. By having a larger surface area as well as having more fluid capacity.

3/4 ton and bigger trucks do this multiple ways.
Larger capacity tranny pans and bigger trans coolers.
Some tranny pans will also have aluminum fins like an old 2 stroke motor to help reduce temps as well.

 

Active cooling would help (a cooler with a fan). To give you a bit more margin, a high quality synthetic fluid such as Amsoil would help too, it has a higher breakdown temperature.

 

I know that on a 2009, the temperature gauge is right after the pump, so it seems worse than it is. I have hit the mid 220s when running WOT up a mountain on a 98 degree day.

 

I was way bad. Over the weekend towing up summit camping my tranny temp hit 242. Going to get tranny flushed and new filter and looking for a bigger trany cooler.

 

Thanks to all for the information.

HotBlue05SCREW, Let me know if you find a good way to replace the stock one. (mounting)

 

Troyer.

 

Has anyone tried to install a fan on the factory tranny cooler?

 

I plan to use a superduty transmission cooler to replace the factory one in my 07 f150 by fabbing my own brackets to mount it. My tranny temps climb way to fast when i offroad at the beach in Texas summer heat. Stopping to let it cool gets old fast!

I don't know if people here have put fans on their coolers but it can be done cheaply if you make your own setup and don't buy an aftermarket kit like Troyers. If you have the money and would rather buy something ready to go then go for the Troyer setup.

Installing a larger capacity oil pan will also help out with the cooling like someone else pointed out. As well as a fluid like amsoil that is more resistant to breaking down from high temperatures, this way it maintains its properties at higher temps.

 

Run a second v-10 granny cooler,problem will be solved

 

Exactly my point...