The Butchers Pal

Hi My 2002 X5 has a vibration & associated noise when you apply light load to the engine in 4th or 5th between 1500 - 2500rpm. If you continue to accelerate the box kicks down and the vibration clears instantly only to reappear when it changes up and gets to the above rev range. Has anyone else come across this problem and if so what can be done? Thanks TBP