Transmission noise and couple of other bits

Just got a 110 (1992) with 200TDi engine. When I am cruising at speeds of around 50mph, and dip the clutch an unusual noise occurs (also at slightly higher speeds without dipping the clutch). Its a grumbly vibration with a slight scraping/revolving noise. There's also a bit of a 'clunk' when changing up a gear - just at the point when the clutch re-engages. Could these issue be linked? Any ideas/help on this would be great.

Also, one other small issue - I've noticed thin brown fluid coming from one of the rear centre hubs - again any ideas/help on this would be gratefully received!

Cheers,

Neil @ Urban Pursuit.

wheel hub ?if its brown oil needs changing and wheel bearings clkeaning and greasing,common if youve been wading ,noise on over run is often diff id check them first ,there should be no end float or play in a diff flange