I have been through this but with a different issue. My advice is read the Lemon Law procedure in your state. You can do this with a simple Google search. My best advice is to contact a Lemon Law attorney which you can do with a Google search also. Normally there is no out of pocket expense depending which state you live in. My state actually had a list of recommended attorneys at the Attorney Generals Office. GM and GM no customer service are not your friends. They will take their time, lie to you and try to wear you down. No matter how frustrated you get don't give up. This is not a quick process. Document, Document, Document. Document all conversations and make sure you get a copy of all work orders. The last thing you can try before anything else is talk to the General Manager at the Dealer and see if he would be willing to put you into another vehicle without a financial loss. If you win the Lemon Law case you should loose very little monetarily which is usually just mileage. If you need any info just ask and I will do my best to help. Good luck.
I have a 16 Denali XL as well and as luck would have it on my side the only issue I have had is with the 4WD needed to be refreshed. It runs quite, and smooth and gets great milage. I have also towed a 7000lbs camper with it with no hic ups yet . I really hope you resolve your issues.
I do have something to say though other than this. Before I went to the big SUV ( had a Suburban before trading to the yukon) I owned a Montana SV6 . The Dealer I bought that from gave me such a run around about everything and anything warranty related I was ready to give up on GM . One of my friends said I should go and see his dealer ship to see if they would do anything for me.. boy I am glad I did . They repaired everything that I complained about with no hesitation and also went one step further and went looking for all other problems that would be covered under the warranty and repaired them as well.
Because of this I continuoisly return to that dealer for everything including the oil changes .They restored my faith in GM .
Maybe if you took it to another dealership they will treat you better. Probably not trade you into a new one but maybe help resolve the issues. Just saying
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