Rep Power: 0

My 2005 Civic SE 1.7L rattles when it gets hot. The sound is not there when the engine is cold or warming up, and only after about 5 minutes of driving. Its is a sound that is really loud in 1st gear and gets gradually quieter while going up the gears. When I hear this rattle and I push the clutch in, press on the gas to rev the engine, the sound is not there (I suspect it is a transmission problem). Now I have just got the transmission changed in April with a used one that had about 150 000km on it. Could this be the culprit of my noise? Luckily, the transmission is still on warranty. What do you think?

Thanks!

John