DS5 noise sounds a bit like a train

[Sparkie11]

Hi All,

I have a DS5 180 diesel Automatic 2017
I recently have had a new cv boot fit and within 14 days of this it's developed like a train sound.
Sounds like the passengers side front, I have had it checked by the garage that completed the cv boot to confirm that the cv joint isn't bad.
They said all okay, but they believe the sound coming from potentially the gearbox.
It sounds worse when I take my foot off the accelerator, coming up towards a junction. (Coasting)
Always been serviced as per the book.
Any idea what this might be?
Thanks

[RichardW]

What sort of train noise?

[Sparkie11]

The noise like a train passing, when you hear the rattling, knocking noise of the wheels on the tracks.