went offroading - did some damage to my front differential

[dna]

Went offroading in teh Wypress area of Alberta for about 6 hours. After getting back to the road I switched from 4 low to normal all wheel and instantly I felt the gear not engage and heard a little grinding type noise. Pulled over and sure enough my normal all wheel would not engage. I was able to put it back into 4 low and 4 high. Obviously this is my front differential.

Any idea where I need to start and what I likely did? The trail was not that rough but there were numerous 2' or 3' mud bogs. There was one spot where I did not see a large pothole and did go through it kind of fast - but that was at the start of the ride.

Again I would appreciate any and all advice. Where do I start.

Thanks