This sounds like it is a transfer case issue. You have what is called a 4Matic AWD system. That means it is normally two wheel drive and then it applies the 4WD system. If there is an issue with the gear or clutch inside the system then it will grind while it is attempting to engage the system. Then it stops a mile or two later when it turns the system off and reverts back to 2WD.
The only way to repair this is to rebuild or replace it.
Have you recently changed any tires? With your system you need to change all 4 tires at one time. If you change 1, 2, or 3 tires it changes the wheel speed and will actually cause issues in the system.
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Saturday, December 14th, 2019 AT 7:43 PM