Popping Sound in 4 wheel Drive

[CoolrainRaptor]

With all the snow went out to day with the new Raptor (4600 miles) switch it to slippery/wet mode (whatever its called) 4w drive all good until I'm turning a corner and need to get out of the way of some guy who blew a light (I'm guessing as I have the green) so I have to get into the gas.... now I have a popping sound, seems to be below my feet and only in 4w (auto or high)
called and made an appointment
Any idea? I'm thinking transfer case or?

 

[CoronaRaptor]

Could be an iwe or a cv joint in the front.

 

[CoolrainRaptor]

Could be an iwe or a cv joint in the front.

Thanks
I just hope the parts are available