whirring noise on car around 70.

[BIG G]

an anoying problem with my surf, for the past month or so ive had whirring coming from the cars through the gears as if there maybe a gearbox bush away or somthin and also at around 60mph through to 70mph if i slip it into 5th gear i get a real bassy vibration but only at 60 in 5th, theres nothin there if i keep it in 4th gear at 60mph, bit of a head batterer i know but thought id post the problem up anyway.

can anyone help.