I had a 2004 z-71.....started having problems at 36,001 miles....
I put up with it for a long time. Eventually, the oil, volt, gas, and finally tach started having problems, too. I read on this board that Chevy was replacing the package.....Even though I had 75,000 plus miles at the time, the dealer where I bought it was good enough to replace it free of cost.....I think they know they had many problems. You might call the place where you bought it and see if replacement is covered for that model too....If I remember correctly, it's the same instrument cluster.
It took 10 minutes one day for them to "transfer and confirm" the info on the truck and 2 hours another day to replace.....I heard the 3 day turnaround stuff too....one of the reasons I waited so long. They replaced mine...they didn't send if off to be repaired.