Got 2020 1500 Duramax.
all seem good but since about 1500 miles there is ( sometimes (pronounced)) thud after completing a stop. I cant seem to duplicate it for any given scenario. Mostly happens with light or low speed stops.

just me?

 

If you've not done anything to it external, take it to the dealer.

 

that's usually binding slipyoke on the transmission output. Definitely falling under drivetrain warranty