Loud noise when switching to 4 wheel drive.
When I switch the knob to 4 wheel drive, there's a
loud beam from underneath the center of the truck.
But it does lock into 4 wheel drive.
My Ford make a thunk when engaging, especially into 4Low.
Could be tansfercase chain slap and that means it’s time for some transfercase work, left unchecked it could break the case. I never put my 4X4 in unless the rig is standing still and on as level of ground as possible with the tranny in neutral and the park brake set. I don’t subscribe to the “shift on the fly” idea.