Vauxhall Corsa loud noise when in d gear

There is a loud vibrating and banging noise coming from the car when it's in drive. This only happens when I've driven the car for at least five minutes and the noise only happens when the car is not moving but still in drive. E.g waiting at traffic lights or sitting in traffic. The car only makes the noise whilst in Drive not moving. In any other gear like N,1,2,R and P the car doesn't make a noise. I was told it might be the transmission fluid but I've checked it and it's ok and the fluid is clean. Very confussed, can someone help me??