i lowered mine with the belltech 3 5 kit and i seem to also have that vibration rubbing sound in the rear as soon as i get closer to 50mph, installer notice that also and he installed a shim on transmission mount i believe? i couldnt quite understand him since they been working on it for like 10 hrs trying to figure it out, as this time i have no clue what to do as either as the shop who lowered the truck. [/url]">http://http://s801.photobucket.com/user/rang3l93280/media/1658650_916903208335602_3359907531639276262_o.jpg.html'>