Paul, I sent a PM to you (see if GM changed the way the 2015 bed is mounted) but then found this old post.
Posters here offer some things to try to help you narrow things down. ( one thing mentioned, the new trucks shocks might be different than the old truck and someone mentioned how to adjust your mirrors to view the camper in relation to the bed)
You need to know if the camper moving in the bed or the bed moving the camper.
You might need a second person to drive next to you . Shoot a video . That's how I improved my golf swing.
Bob
