I have a 2012 2500hd. Can't get my dealer to change theTPMS setting so I've messed around with it to get it as low as I can w/o light going off. 49psi in front tires 60psi in the rear will not trip the light. Mine is the vortec not duramax though don't know if that matters or not.
Hate the TPMS. in all my pickups I've never run over 40psi in my tires, Why feel every crack in the road. Now I just leave it at them pressures but when I'm out in the hills hunting I drop them all to 35-40 psi and deal with the light and hitting the button four times when I start it up.