I have been waiting for someone to post an issue like this. I bought my custom trail boss back in September everything was great, then came the cold weather. I noticed this "clunk clunk" sound coming from the front end on uneven terrain. I took it to my dealership and a few techs drove it. They told me the same thing it was the right front shock and ordered me a new one. It took well over a month waiting to get the part and during that time the noise stopped! (WTF right?) Now, the weather did get a bit warmer so I figured I would just wait and see if it comes back.
They called me when the shock came in but i told my adviser that there was no more noise and he said "great, then lets not fix what isn't broken". I was fine with that until... the weather got colder and I washed the truck, boom it was back and louder. So... I have been testing it out with the temperature changes and washing, I only hear the noise when its cold and after a wash. I will be taking the truck for a oil change and the recalls here soon and I'll explain to them what is going on. I see your from a much warmer climate and now I may have to go back to the drawing board.