Can I buy a warranty for my 02 GMC and use it to make existing repairs?

sure , no one ever thought of that just think pay 3 grand for a warranty and do 5 grand in repairs? whats going to happen is they will have your money and you will still need to repair your vehicle routine maintenance and parts that wear out or break do not count. What this means is you will get scammed out of your money upfront and then when repairs are needed they will look for reasons not to repair calling it normal wear and tear or even mechanic cannot reproduce problem or some other excuse to do nothing My daugther worked for a dealer with multiple manufacturers some of them would have the dealership go through the repair history with a fine tooth comb looking for missed oil changes ( or better yet late ones) trying fo find a way to deny a valid claim.

Yes you can buy a warranty for older vehicles but at the same time they may request that the vehicle be checked out by a licensed mechanic before approving it.

do you have no common sense

warranties start the day you buy them

no way