| Id say its normal! Your probably hearing the truck suck air through the less restricted air filter and housing. No leaks or anything.
There is a way to check for leaks. Get a can of starting fluid and with the truck runing spray A SMALL AMOUNT of starting fluid around all the connections. If theres a leak the idle on the truck will raise.
Another thing to look at. I also just recently heard the older duramax's have a peace of metal that rubs through the intercooler tube that runs along the front frame.
__________________ Jason 2006 Silverado 2500HD LBZ CC SB Escalade Handles, Front windows tinted to match the rear, painted bumpers, billet grille 4 Kicker 10in Subs in 2 custom box's, Autometer Ultra lite II Pyro and Boost gauges MBRP Turbo Back Stainless Exhaust (Straight piped), w/ stainless tip! PPE Hot+2 285/75/16 Nitto Terra Grapplers on Gear Alloy wheels ****Lost Kitty Reward if found!! 1999 Ford F-550 PowerStroke ''Wrecker'' **Jerrdan bed, S&B Intake  |