2002 tahoe 4 weel drive

Driving down the interstate yesterday my setrvice 4 wheel drive light came on. Parked the vehicle over night and wghen i started it up this morning it was in 4 wheel high. I can't get it out. Is there a simple step?

First of all, welcome to AF. Please make sure you've read the AF User Guidelines (http://www.automotiveforums.com/vbulletin/guidelines.html) and post your question in the appropriate forum (Tahoe).