Rattling thumbwheel on 5d mk 3 ?

[Canonian78]

Hello.
I just got my new 5d mk 3 couple of days ago. I notice, that when I'm turning the big thumbwheel on the back, there is a variation of the clicking sound. It's not going all the way (360*) on the same noise level. It's feels like its going smooth for 3/4 of the round and the rest sounds like a much stronger clicking. Is this something to worry about?
Is there anybody who notice this?

 

[Mt Spokane Photography]

There could be a mis-moulded part that has some surface defects. its not likely to ever be a issue, but you have a limited tome to return it, so you might want to exchange it for peace of mind.