poss gearbox prob/noise????

[dab72]

help needed as nova has developed a humming noise seems to be more noticeable at around 40mph and 70+ in 4th and 5th can't tell in other gears.first thought it was wheel bearings but replaced them and still have noise. a few people have suggested diff bearings is this a common problem? it's a 93 nova 12i has done 60000 mile car has not been thrashed buy me or previous owner. help! :?

[Stuart]

mine makes a racket at 50+ in 5th i topped up the fluid and tahts not changed a thing. to be honest i cant be arsed to find out what the problem is as im going to ahve it all stripped and "adjusted" soon (i hope )