ticking from gearbox

I have heard that the passat has its fair share of gearbox problems. I have noticed mine makes a fast pitched ticking noise which starts about 15 seconds after start up. The car drives perfectly and is not noisy when running. Anybody have an idea what it is or had the same problem. I presume if its not a switch of some description then its a bearing or layshaft problem. Any advice will be appreciated
ps the noise seems to go louder and quieter at idle when the car is still:1zhelp: