snot normal and dey dunt all do dat.
start at the wheels , check drive members , half shafts , diff flange , uj's , prop splines , tranny box flange and if that don't sort it there might be play in your gearbox main shaft , pop the inspection plate off your tranny box and check the input gear for wear.
drive members don't cost much , props are a little more and input gears a bit more than that but a small amount of play in all three will cause the symptoms you describe. i had **** loads of drive train shunt in mine and i replaced all three of the above and it sorted most of it , my gearbox main shaft is badly worn so only a new gearbox will sort that.