a8 problems PLEASE AID AID

have problem .
when the car starts it makes a rebuke as if the starter is stuck. and when I start the a8 4,2q hanging gäreuche as if the at metal grinders would, that goes so on until the warm is about: 90 degrees.and if I drive the car up, I believe that the car runs through when switching.and if I turn off the ignition it is all normal until I give full gas. then the thing starts from the front.(is that a gearbox hurt or an elecktrick harm please answer 01795333359