Jaahn, I know I can be a pain in the A-se, but during my life, I have questioned many engineering situations, and also been able to make changes that have improved the situation. So it is, that I cannot just except the way transmission coolers are fitted to the diesel utes. Namely fitting the cooler in front of the intercooler. I cannot see how we are improving efficiency by taking heat from the transmission, and feeding it back into the inter-cooler and to a lesser degree the engine coolant radiator, not to mention the air con condenser. This setup which would have worked ideally in the days of petrol engine cars with no air con, has just been ported over to make do with todays diesels.

Australia can get hot, very hot, and in those conditions the outside temperature is doing everything wrong for engine efficiency, so I don't want to add to that. In cool conditions the cooler in the front would work. Fitting a cooler under the car is not my ideal, it is subject to water, flying stones and the chance of being caught up, but its the closest space available.
Your comment about the fans cutting in when in traffic, is exactly my point, one is traveling so slow, there is no ram air to the front, but temperatures escalate, same as following a slow truck up a steep long incline, and that's when the fan assistance is required.

There is another spot that is possible, and the place I would prefer, but the length of hose or tubing would be in the order of 6 meters supply and return. I have attached a picture. I have emailed a company in the states, asking them if the 6R80 transmission can have this length of tubing, your comment is appreciated here if you can help.