I must be slow. I don't get it. How will adding fluid help?

A pan won't cool the trans, so I'll ignore that. A "cooling pan" is an invention of someone that doesn't understand thermodynamics or fluid dynamics, i.e., they are just guessing.

 

Actually, I think we're the slow ones. We're thinking more fluid, more time it'll take to heat up. But at the other end, once it's hot, it'll take time to cool it all down again.
When I had my tranny rebuilt as "bulletproof", I had the shop go ahead and put on the Derale 14208 pan. When I got the truck back, I noticed they had also installed two coolers in front of the radiator and that they had completely left the radiator out of the system. It does take some time for my tranny to warm up when not towing heavy and does not go over 140 degrees on the gauge even with a light trailer on. When I have my 19K loaded trailer on, I've had the gauge go up to 200 degrees and that's when going from 100' in elevation to 2500' in 20 miles, 35 mph to 55 mph depending on how steep the grade. When I reached my destination, I let the engine idle to cool down the turbo and tranny, and the temp did come down slowly. This was before I changed out my exhaust to 3" downpipe and 4" flow through muffler. We'll see what she does next time I tow that route. Normally towing that heavy load, tranny gauge will show 170 to 180 degrees on trips with less elevation gains.

 

I want to add my 2 cents to this discussion. I'm thinking about buying the Derale for the rebuild of my transmission.
I agree with Mark. Friction of the transmission adds heat to the fluid, and the cooling system removes heat from the fluid. On a long sustained run the fluid temperature will reach equalibrium no matter how much fluid is available, because the heat added will equal the heat removed. Increasing the capability of the cooling system to remove heat is the ultimate solution to overheating fluid.

However on shorter runs and when going up & down hills, additional fluid will help keep the temperature lower. How many of us are long haul truckers? The measurement that we need is: How long does it take to heat the fluid to equalibrium & how long does it take to cool it again? The actual operating temperature could be less than the equalibrium temperature, and the amount of fluid available will affect that, as well as how does the load vary.

As I said before, the ultimate solution is to add more cooling.

 

I know this thread is long dead but I'll add something to it. The thick cast aluminum pans actually add quite a bit of strength to the case to keep it from flexing when there's big power running thru it. That's a big reason why I run one. The deeper but thinner pans probably would be weaker in that aspect.

 

I added the 6.0 cooler. it was easy to do. Well easy for me. If you have a fix it kind of mind you will do just fine. if not there are plenty of people here to help you.