Passenger rear suspension issue

[Moose12]

Hey guys, new to the forum. Figure someone may have an answer to a nagging problem that My dealer refuses to correct.  2019 GMC AT4, 20k miles, passenger side rear suspension feels like it’s bottoming out.  Hard slam over dips in the road while empty.  Slams hard enough to need a chiropractor with a sled trailer and 2 machines on it. Been to the dealer several times now. Can get it to duplicate with service writer in the vehicle (of course not as often as I feel it when he isn’t in the truck). They claim it’s normal function.  I differ from their opinion.  They have replaced bushings in the spring pack and replaced one of the shocks in attempt to fix the issue. The passenger side seems to shimmy, shudder or resonate after hitting a bump while the driver side rides smooth as it should. Makes a metallic rattling noise sometimes depending on the bump.  
 

After the second visit to the dealer and their attitudes toward this being a normal function I filed a complaint with GM customer service. Been back and forth a number of times to GM customer service, they contact the dealer, then call me back.  We aren’t getting anywhere.  The dealer wants me to load my snowmobiles on the trailer and bring it to them so they can test it with the trailer to which I said no unless they want to cover any damages to the trailer and sleds if something gets broken.  The dealer declined covering any damage to my other equipment so that’s at a stand still right now.  GM trying to find another GM service center to see what they can find,  but closest other dealer is 350 miles from here but they won’t cover any costs to get the truck there and back. 
 

Over lunch one day a co worker and I mounted my go pro under the truck and took it out and got some decent video of the shimmy, shudder, or whatever you want to call it in the rear spring pack as well as some of the noises I’m hearing. The tires seem to bounce after certain very small bumps and cracks in the road. The only thing the video doesn’t show is the horrendous thud that is heard in the cab when it feels like it’s bottoming. 
 

I know I’m not the only driver in this area with the same problem. Unfortunately the other guy I met with the same issues is getting the same run around from the dealer and GM customer service.  
 

Does you guys have any idea what could be causing that side of the truck to feel like it’s bottoming so hard even after replacing the shock? I will also add that being here in interior Alaska it gets darn cold and the bottoming is easily twice as bad when it’s cold outside.  Even when coming out of a 65 degree garage.  

Seems like it’s a miracle to get this dealer here to fix anything even under warranty.  It’s almost appalling that you can spend that kind of money on a “professional” grade truck that can’t handle towing a 2 place snowmobile trailer without crushing your spine. 
 

I will try and add the video if I can get it uploaded to YouTube

 

thanks in advance.  

[swathdiver]

Change the shock on that side.  If you still want to wrestle with the dealer, pick another one.

[Moose12]

The shock on that side was changed by the dealer a month ago. Wrestling with this dealer is not the only option, but close to it given the next closest dealer is 350 miles away in Anchorage.