So I’ve been chasing this nasty ear splitting drone my 97 F350’s been making the last few weeks. Doesn’t start until about 55 mph and is the worst at about 60. Use to taper off over 60 but it hasn’t been tapering off as much lately. Makes the truck almost unbearable to drive long distances it’s so bad now. Everything on the exhaust looks good, and it’s all stock less the 3” down pipe. But I don’t really think it’s coming from the exhaust as I hear it more from the general area of the turbo/rear of the engine compartment. I’ve checked the inlet side of the turbo and doesn’t have any end play and I can’t see any fins missing. Turns freely without any hiccups. Have yet to take the down pipe off the exhaust side to check those fins. I’m at a lose as to what else to check besides the front axle. Engine runs smooth and has plenty of power. Any help is appreciated.