hi my names nickrob and live in east sussex. just aquired a 2004 f.l. td4.getting a noise from the car which sounds like back axle, but have been told its tyre noise and i should change the 16inch to 17inch. any advice would be greatly appreciated

hi, just enlisted and apart from saying hello, im having a problem with my fl, its a 2004 td4 and there is a whinning noise which the garage told me was to change the 16inch wheels/tyres to 17inch. to me it sounds like back axle but im a novice..any advice would be most appreciated.