[Paul Glasson]

Can someone describe the symptoms to identify if a crown wheel and pinion is going, if the box is still good for 20000+ km once the wear becomes noticeable,and if there is any adjustment to take up slack or it is a throw out and replace item.
Symptom I get that is staring to be noticeable but nothing serious now, is on running against compression,especially in 1,2,3 there is a gear meshing hum,which goes away when I accellerate in each gear. I would not describe it really as a whine, more a gear meshing hum. Shifting & everything else fine.
Car has 173000km, not driven that hard by previous owner and me with occasional autocross (every 3 month),has synthetic mobil oil in gearbox with scheduled oil changes done if Porsche agent did do the change.
From reading posts this would appear to be one of the weakest points of these cars.