2006 Sierra 1500: Scraping Noise After Transmission Service

[Ragnarok]

Just had the rear main seal, and the transmission output seal replaced which meant the transmission had to come out completely.
Everything looks and feels fine, except now there is a grinding/scraping noise coming from either the transmission output or where the drive shaft meets the differential. The noise is louder at slower speeds.

Do new transmission output seals need to be "broken in" and such noise is normal? Otherwise, it's back to the dealer.

[muddkatt]

Take it back to the dealer, there should be no noise.