audi 80 b4 2.6 v6 gearbox

[v6 si]

Can any 1 throw any light on this subject?
Since I have had the car the car(and a beauty at that) there has been a slight noise that I am presuming is coming from the gear box. Now this noise isnt loud and isnt a whinning noise either, it sounds like the noise gets faster with speed but not louder.I have no problems selecting a gear or changing gear, I am wondering if I ,may need gear box oil? and if so is this a tricky job?(may sound like im stupid but some 1 told me it might be a nightmare of a job) Me and the beast will be at the audi meet in August, so if any 1 can help you can have a listen......cheers Si