Hello everyone I am new to the forums I hope im in the right section recently purchased a 2006 GMC Sierra 2500hd crew cab long bed with 256k miles and the truck is rust free. I purchased the truck for a good price due to a problem that it has. The truck runs and drives great but im hearing a whooping sound from the air box and slightly louder than normal tick from the passenger side of the engine and im not sure where I should start or what I should do. If anyone can point me in the right direction on where to start.