My brand new 15.5 Denali 2500HD d-max.... and it's 2 persistent pe

[OVRBST]

Hey guys. Just picked up my new 2500hd Denali. It's the 1st new truck I've ever owned and i chose it after a bunch of research. I love the truck other then this damn shake at 68-78. Brought it to the dealer at 1003 miles and at 1300 miles. Can't shake it (pun intended). New rear tires helped but it's still there.

 

Also have this silly little thing where the driver seat feels "loose". Just the seat back. Hard stop or aggressive braking you can feel the seat come forward then when you stop or let off the brakes you can feel it sort of fall back. It's maybe 1/2" of movement but it's annoying. The dealer put a shim kit in but that did nothing.

 

60+k trucks built on the "professional grade" premise shouldn't do this. My 08 F450 rode smoother then this truck.