Hello All Please can anyone shed some light on a mystery noise I have in my XJ8. When the car reaches 60mph a cyclic rumble starts continues to approx 75mph (worse at 2400rpm - 67mph). If while experiencing the rumble you select 4th gear it virtually disappears. I have had the propshaft balanced, wheelbearings checked, whole drivetrain alignment checked, 4 wheel alignment checked, changed to 4 new tyres, rear dampers changed. all to no avail. The car drives superbly in all other respects. Specialist and dealer can't find the problem. Has anyone had this issue. All help would be much appreciated Dale