I agree with others on adding what is referred to as the 6.0L trans cooler. Matter of fact I just purchased one yesterday to add to my 2003 6.8L V10 with 4R100. Just shy of $300 at dealer. You can also get from one from Dorman for about $180. I went with Ford OEM. Both of these coolers are direct bolt on in place of original cooler with only (2) 3/8" to 1/2" hose barbs and some 1/2" trans hose needed for plumbing.
I also added a ScanGaugeII and can monitor trans temps very accurately.
You many want to consider these two items if you are towing.