help wierd noise!

[Aimez]

Was driving around today at about 50mph in 4th gear and i could hear the car making a really loud bassy tone almost like a silly exhaust note sound! I took my foot off the gas and it still sounded then just went away.
Had this happen a few months ago and maybe more times since but i normally have the music up loud so probably havent heard it.This is my first diesel so don't know what noises to worry about or anything about turbos?!
I hope theres nothing wrong just forked out loadsa money on the brakes!

 

[muddyboots]

If it happens in 4th gear, it's most likely the gearlever rattling, well known problem in Mk4 TDIs...mine did it really badly.

 

[Aimez]

it definetly was an engine noise thou not from interior at all like i say sounded like a chavvy exhaust!