Crunching sound behind dash

Hello to all. I have a 03 TB-48k miles. Just bought it and noticed a crunching noise behind dashboard when i shut the engine off . I took it to the dealer where I got it .They say there is a short back there and have to replace instrument cluster-$275-not under warranty.:frown: .I then took it to another Chevy dealer who tells me there's nothing wrong it, the noise I hear is my instruments resetting themselves. Don"t kinow who to belive:banghead: .Does anybody have any ideas ? THANX

A hiss noise on s/d is perfectly normal. It is the motorized tach coasting down. No worries.

Joel