Brought mine into the dealership last month for this problem twice. First time they tightened everything down in the rear end, took them an hour to do so. Then right when I got back into the truck and started to leave the parking lot, it did the same damn thing. Took it back a week later and they lubricated the leaf springs with some heavy duty grease and the clunk, clink, bang noise went away.Talked to the service guy and he said if the truck continues to do it, they can look into further options, or they will just need to lubricate the springs on a regular basis. A month later the truck is starting to do it again. If you spray some WD40 and coat the springs pretty good while getting the oil in between the springs it'll stop the noise for a couple of days until they get dirty. I also found that when the springs are wet they do not make the noise as the water is acting like a lubricant. Hope this helps.