slight vibe and roar

lately i've been getting a slight vibration on the floor board when accelorating and a slight roar in the rear while driving. when I drive around with quite a bit of stuff in the rear the sound isn't as bad as when emtied out . any suggestions

we need to know more about your XJ... what year? lifted? if so how much? what drivetrain and so on....


Kejtar

sorry it's a 92 xj ,no lift as of yet 4.0 L ,8.25 rear, comand track
Iwill be installing a 4.5 lift this saturday so I would like to resolve this by then , so can you help anyone ,anyone