Alright, weird noise investigation. Truck is a '13 cclb F350, 6.7. Deleted on a stock power tune.
Trying to catch a video, but no luck so far because it's so random. I'll be cruising down the highway at about 1/4 throttle, usually in 5th or 6th. About when everything gets up to operating temp, and all of a sudden the truck will start a shimmy kinda like an out of balance tire, but it's got a metallic rubbing/ grinding noise that goes with it. As soon as I give it any throttle and it downshifts, the noise and shimmy goes away. It's coming somewhere from the engine bay, kinda sounds like it's more from the passenger side. At first I thought a sticky brake or a wheel bearing, but the bearing seems tight and this will happen when I haven't touched the brakes in a couple miles. Seems to be more prevelant in higher gear/ lugging aituations, got it to happen for a sec in their doing about 25 up a hill with 4 horses in the stock trailer this morning. But same deal, give it some rpms and it downshifts and goes away. Pulled the belt and started spinning pulleys, everything felt great except one idler, it had a little wobble so I swapped it out. No change. Hubs are both unlocked so I ruled out a front driveshaft u joint. Trans fluid was changed probably about 8000 miles ago. Still full, smells and looks good on the stick. Anybody else had this noise/ found a soultion?