At the drive-through, stopped, and noticed this for the first time:

When in gear (Reverse or Drive) and stopped there is a slight squealing noise, like the serpentine belt. Strange though that when I put it in Park the squeal goes away.
Recently had the dealership install a new belt tensioner...possibly not done correctly?

Wondered if anyone had experienced something like this and it wasn't the serpentine belt?

'05 CRD

Thanks!