Recently I've noticed a 'strange noise' coming from the front left wheel. The noise is only apparent at low speeds, especially noticable when reversing with hard right hand lock and also when accelerating from a standstill. I've jacked up the front of the car and I can't see or feel anything loose. Does anyone know what may cause this issue? My car is an 2008 A3 2.0 TDI 170 Quattro with about 44,000 miles.