My rear end clunk is complete gone now. I replaced a rear sway bar and end links with hellwig unit, replaced all of nuts and bolts on lcas and shocks. Also replaced an adjustable panhard bar back to stock. It has been almost 2weeks since and stil no clunk.
2012 mustang v6 performance package, power mods: airraid intake, borla s-type exhaust, appearance mods: saleen front grille, hood spears, roush side spliters, 2013 tail lights, retro fitted head lights with led and hid, shorty antena, black deck lid, gt500 steering wheel, oem take off leather seats, retro black shift knob, suspension mods: koni shocks/struts, sr springs, gt500 top mounts, panhard bar, lca.
1994 mustang gt 5.0