Transmission/Clutch

My car makes noise when the stick is in nuetral but once i push in the clutch it goes away i also hear it when i downshift form 3 to second gearand when i put it in to first. It's not a grinding noise but it sound like something is rubbing more then it should. My friend has a civic and it doesn't make the noise.The car drives fine but it is now worrying me. Honda said to replace the carrier bearing but they did not give me any more helpful info about it. Please tell me what a carrier bearing is and how soon should i get it fixed and what it does.

I dont know