New work truck, 2022 3500HD, 6.3Hemi. 100 miles on it. Since I picked it up with 30 miles on it, it has been making a hissing/squealing noise only under load and it seems to be coming from the AS66RC (?) transmission? I can't hear it under the hood as it only makes the noise in gear and under load, even the slightest load and it will be audible and it sounds like its coming from under me or behind me. It changes pitch when the gear/RPM changes. When I coast or barely feather the throttle I can make it go away but it's bugging me as this is brand friggin new but did sit for a year in a lot before It was assigned to me. Darn suspension is as stiff as a buckboard , I can't drive with a coffee in the console without it shaking out when driving down the road...small price to pay for a new truck I suppose.
