Noise in reverse.

You hit the garage door.















Actually, mine does that from time to time too. You can minimize it by shifting to first before going to reverse. I don't know the cause, sorry.

 

Probably that you have a very slight amount of drag in the clutch assembly -- i.e., you're in neutral,
clutch pedal is "up",
the engine is running,
you press the clutch pedal down, but the slight drag keeps the intermediate clutch assembly rotating,
you try to select R,
clunk occurs because output side is stopped, but intermediate stuff is still slightly rotating.

Just select any forward gear, as Tillman suggested, to fully stop the intermediate clutch assembly rotation, just before selecting reverse. (It's really kind of "normal", and wouldn't need specific attention unless it got so bad that selecting 1st when stopped got difficult too.)