2012 F150 4X4, had the clunk since i bought it and after repeat trips to the dealer gave up on fixing it and just lived with it, well after nearly the best part of 170,000km the clunk is there and driving me nuts, this past week i have gone though the whole truck from bumper to bumper, even tried the ford TSB with grease for the slip yok, made 0 difference. Got a whole new yok made no difference. Replaced the Spring UHMW wear pads. The problem i have is sometimes it does it then others i can go days without the issue, the only thing i can narrow it down to is it happens when i accelerate from a stop and if i stop fairly hard (not locking the brakes though lol) any ideas on anything else. I'm assuming due to the amount of km i have driven with the noise it cant be nothing too serious just annoying as hell.

 

Did you check to see if your spare tire is loose? It may be moving around when you accelerate and iron and stop a hard making that noise. Or it could possibly be your leafspring shackle's where the shackle and frame meet or where the leaf spring and shackle meet.