I just picked up a new-to-me 2020 5.3 Trail Boss. 37k miles. When driving it, somewhere in the 25-35mph range, it always sounds like a dang helicopter under the hood. Doesn't really do it above or below that speed, so it makes me think it's not the bigger tires (that I'm not use to yet), but I don't really want to pay a $160 diagnostic fee if it's something normal that I'm just not use to, so I figured I'd check here first. Seems like right around that 30mph area, letting off the gas, or maintaining that general speed, the truck sounds like a helicopter. I don't know how else to describe it, but similar to what you'd hear with big 38" mud tires going down the road, and loud enough to be annoying and make it tough to hear the radio or my phone. It doesn't drive strange, feel strange, just sounds loud.