1997 XJ8 3.2 SPORT rear vibration

[SEASPANNER]

Hi there,my car has developed a bit of a vibration from the rear.
Only comes in at 85 mph and phases out again at 95-100mph.
I had the wheels balanced but this has made no difference,there are no abnormal noises etc,car she has done 73000miles,seems to have come on the last 2 or 3000 miles.i greased the driveshafts but no change.Any ideas??
Cheers

[Trooper2]

For starters, do a tire rotation and see if the vibration moves or goes away.

[SEASPANNER]

thanks mate,good thinking,can't believe i didn't think of that.....what a muppet,used to be a mechanic too!!!!!!
cheers