01 Denali front axle binding

I have a 01 Yukon Denali XL with an odd problem. After driving about an hour or so on the freeway, I get to where I am going and when pulling into a parking spot the front axle seems like its locked in. It turns like old style 4x4's when the hubs are locked in. Can this be related to the switch on the front axle heating up or might this be somewhere inside the differential? Thank you.