cheddaboy

So I recently started hearing this pinging/rattling sound comming from my car. It almost sounds like cards in a bicycle Wheel. It only happens while in gear and doesn't go away until I've come to a stop. It's also very pronounced when driving by cars or walls etc. The most recent work I've done on the car before hearing this was swapping my stock rear bumper back on. I highly doubt it's the clutch buzzing. The TCT could be the culprit but I highly doubt it makes noise while driving. My rad fans are intact. I'm going to jack the car up this weekend and see if I can pin point it, but I hope someone can pinpoint what it can be.