TD5 manual makes helicopter rotor noise

Hi Guys I would appreciate your help....

Had this disco my one and only for over 2 years, changed the injector loom and that's it.
I have a noise that seems to be getting louder its almost like helicopter rotors. (Blackhawk down) it's road speed not rev related. It is only active on acceleration/cruising and most pronounced at around 30-40 mph. There is no obvious vibration.
Anyone had this before?

Hello and welcome,post up in the discovery section with your problem,if its road speed related it would sound like hub bearings/gearbox/transfer box issue

Thanks Henry

I have posted in the disco section. Hopefully admin will tidy this up for me

Regards

Phil