rattle like sound from under car at 100+ spped

[bloodylegend]

hey guys

my car is making this rattle or vibration from underneeth, i can also feel the rattle with my feet when my feet are on the floor. it only abouts about 110kmph and only when my foot is completely off the accelerator. if i press the clutch down the sound stops. and it only happens in fifth gear, ive tried the other gears and its only in fifth gear at 110kph. it seems to be getting worse too the more i drive it. can anyone help with this?

[Brett_jjj]

Check the driveshaft, uni joints and centre bearing for any movement or wear etc.Also check the engine and gearbox mounts.