I have a 2019 F250 6.2 with 16k miles bought new in Feb 2020 that has now been in the shop for 4 straight months trying to fix this noise. It sounds like a Jake brake when in 4wd and decelerating. Dealer has been great, they say its loud and not normal. To date the front ring and pinion, driveshaft, transfer case, wheel bearings and now the entire front axle have been replaced. Filed a lemon law claim but Ford Corp has been awful to deal with. They denied my claim twice citing that it is over 12K miles which is the lemon law statute in SC. Ford has been stonewalling for months now, I cannot get to anyone who seems to care or is willing to help. Dealer even filed a buy back claim and Ford denied it. Ford's stance is they will keep replacing parts until its fixed. What BS. I have been a long time Ford customer but this one is the last. I cannot afford an attorney so I am stuck waiting for a resolution. Deplorable customer service from Ford Corp. My goal now is to simply spread the word about how Ford Corp treats long time customers. I could write a book about this saga and Ford Corp and how horribly they have handled this situation, but I suppose this is not the place.