My terrain shifts very hard and jerky and noticeable both stopping and going fast or slow doesn't matter. I am aware of this everytime I drive it and its distracting

transmission mounts and/or engine mounts are comprimized. Poke at them with a bar to see how they move.

Is that normal in a brand new car?

well we don't know what was done to it before, do we...like if it were a RENTAL, like my car is you can count on every system being abused.

take it back to the dealership and invite the salesman to see how exactly the vehicle he's so proud of representing does after a few months.

its still new,is that the way they all drive? maby a reflash needed to the pcm, call gm ask if a tsb out on this yet, or dealer service for any revisions

only after you poke at them transmisson bars

Have you taken it to your GM dealership to have it checked? This should be covered under your warranty. I would be glad to schedule an appointment at your dealership. If so, please pm me at socialmedia@gm.com ATTN: Vanessa with your first and last name, the last 8-digits of your VIN, address, current mileage and the involved dealership. Vanessa GM Customer Service