Def tank clunk/noise

[dmt0707]

Hello 

I have a 2020+ 2500hd LTZ.  While driving and stopping I can hear a clunking sound from under the truck.  I came to the conclusion that it’s coming from my DEF tank.   I believe it’s the fluid moving back and forth or something else moving around. It doesn’t matter how full of empty it is.   I’ve owned a diesel before with a def tank and have never heard a sound like this from the tank.    I mean the slightest stop, and I can feel the clunk in my feet.    

Anyone else have this same sound ?

thanks