5th Gear rattle (mk4)

I have an 04 jetta TDI with 5 spd and the 5th gear is rattling now. I can drive in all the other gears fine. I am planning to pull the 5th gear cover this week. Any ideas what I might expect broken? I can still get in 5th and drive but it doesn't sound good.

Thanks
Richard

many times ive seen the bolt come off the 5th gear...the one that holds the gear in place

it gets loose and just sits there...thats what might be rattling on your cover