rlaspinall
Full Access Member
I have 200k on this 2011 6.7 liter Lariat. Recently I've noticed a slight chirp under the hood on the occasional acceleration. also heard it once when running in Tow/Haul, started an incline, it kicked down into a high RPM and it did a fairly lengthy chirp during that change. I first thought of the turbo, but it never makes any unusual sounds when under heave boost and seems to be RPM driven. Any thoughts... serpentine belt? tension pulley?