Im new to the site and see this is an old thread. Since I've got my Silverado I have been researching things and find my google searches bring me to this forum quite a bit. Figured I would try to add to the great info I have found here.
Ever since I hit about 2k miles I noticed a faint squeak noise when it shifted from V4 to V8 mode. Happens pretty much every time. I took it in for its first oil change and told the dealer about it. They put about 20 miles on the truck doing tests. They diagnosed it to be a faulty adaptive valve in the exhaust and are ordering me a complete new exhaust cat back. I tried to work with them to some how get a credit towards aftermarket but that was a slim chance. Glad they are fixing it though.
