2014 GMC sierra crew cab rear end clunk

[jj5253]

I drive a 2014 gmc sierra crew cab. bought it with a clunk in the rear and have since then replaced the leaf spring hangers (because one snapped in half), and the shackles. i have also greased the leaf springs with suspention grease, along with everything else that could be greased. Tried cleaning them numerious times. have also retourqued everything along with u-bolts. But still no joy. Never trully thought it was the leaf springs becasue of how it feels and sounds. you can really hear it when driving over cracks, bumps, newly patched road. almost like when my rear end drops back down, something in the suspention is loose or worn and clunks due to it dropping faster than the worn part so a clunk occurs. hard to explain but i have been told to replace the shocks. i truly dont think it's the springs but if anyone had any ideas i would help out greatly, thanks.