While I remember about it...I was sooooo pleased I changed the rad and added the extra auto box cooler. Not really for the mountain tracks, but for the motorway hills. On the flat on the motorway, temp would hover around 82 ish degrees. Some of the long climes caused it to rise once to 94. This is only because i tried to keep the speed up going uphill and put the thing under quite a lot of load. After this, on similar long climes, i dropped it out of O/D and used the box as a manual box keeping it in a lower gear, dropping the speed but also the temp.
Off road, no problems at all up or down, usually below 80 degs.
The only problem we have with the truck now is we managed to pop a transfer case bearing seal by the looks of things, (changed into reverse with out stopping as wifey sent me the wrong way....what she meant was Right, my right, not hers (left).........lol Still replacement set on order.