E53 4.4 2005 - Low speed gear noise independent of vehicle and engine speed

[Flyingdutchman]

Hi

My 'Betty' has developed a new noise. Most obvious is around 30-35km/h. When slowly accelerating or when going constant speed I suddenly hear a gearing noise appear and go away again. Like something is speeding up or engaging, then disengaging again. Its not related to either vehicle speed or engine speed and I don;t feel a jerk or anything, smooth as usual.

My gut feeling goes to maybe the 4x4 engaging and disengaging, maybe that plastic gear is broken again. Changed it 6yrs ago when I bought the car.

Anyway, maybe it rings a bell to someone. Or I just need wait for some warning signal to come on,

cheers