March 2019 Ranger... Two rear ends in 54k miles. Axel seals seen to be a problem. If wheels on one side look darker than the other side, there may be a problem. Also had the bucking & surging problem.
Two words of advice... Extended warranty. My 2019's first diff lasted 33k. I immediately purchased an extended warranty. Good thing, that new only lasted 23k. This time it was a seal leak and they replaced everything.