the backlash is from the detriot. All the detriots that i have seen with my own two eyes have that. You can turn the driveline 1/2 - 3/4 turn, mine does that too. The metal shaving i don't know about. I would just run it and change the oil agaon in another couple weeks. Maybe the oil just flushed the shaving out becasue it was sitting for awhile?