ubernin

2017 Colorado Duramax 44k miles hello everyone, I'm at a loss for ideas and apparently so is my dealership, so im asking if anyone has had this issue before. one day I started my truck up and I heard a weird metallic THUMP for a split second. I turned the truck off and restarted and it didn't do it again. when coming to a stop light i heard the metal THUMP again coming to a stop and then again when i took off. also while driving home and coasting into a turn (no gas just brake) I heard the noise again. before I hear the noise I can feel when it's going to happen. it's hard to describe but it's as if you can feel a weird sort of....tension?...in the pedals and steering wheel. I took it to the dealership and the "gm techs" told the maintenance department that it was the values in the transfer case and to switch those out. I picked the truck up, took it home....no issues. next day I start the truck up again I hear and feel (very prominently) the noise again.... almost like two hollow, metal tubes hitting eachother. however, now it's very prominent when I'm driving. the noise feels as if my front end is fighting itself to sync together. when this happens, coming to a dead stop and a few seconds after....the front end vibrates/rumbles and you can feel it on the pedals and steering wheel. the rumble/vibration is loud in the cab so I can imagine it is equally or more audible on the outside. I made another appointment for them to take a look but this is very frustrating because it's been a month long process for them to ultimately not fix my issue and make it worse. I'm going to try attaching a video to this questions and listen closely on the startup. that's the noise it makes but it's louder and more rough now (with the added symptoms) truck noise