Hi Gary
Welcome to the forum!, I've moved this to the A5 Section for now, Sure this would be the correct location.
As Magnet has stated, is it an automatic?
Are you able to supply us with a video at all? phone on car seat and record sound?
Does it make the noise when you take your foot of the accelerator then re apply? (when you're cruising and not taking your foot of to change gear)
Best Regards
Bradley