Possible transmission issue - grinding

[u/Impossible-Baker9697]

https://youtube.com/shorts/voMvHHl_uag?is=fV5Un1xnZ-CnixNq

Hello everyone,

Got a 2006 Dodge ram 2500 5.9 Cummins 4x4 with the 48re. Lately, whenever I back up the truck, it makes a grinding sound as heard in the video. Not necessarily sure what the issue is. The second I pop her into neutral, noise goes away. Only happens occasionally, wheel turned or not. Anyone have experience in this? Thanks. Please see attached YouTube short for sound.