I am writing on behalf of my Son, whose computer is "down". I am not sure if this is the right place on the website to do this. He has an Audi A4 Advan SLine 2006 automatic with 25.400 on the clock. It has recently developed a grinding noise, particularly when the accelerator is depressed. It has been serviced by the same garage from new and they have told him that after putting it on the ramps they cannot find the problem. They have advised him to take it to an Audi dealer - they suspect that there may be some movement in the crankshaft or a gearbox problem. Would you have any experience of this and. of it does turn out to be this, should it occur in a car of this age and mileage?