AWD issues in snow

[ctland08]

I have a 2004 Tahoe with awd, stabilitrak and traction control. The truck has about 126,xxx miles. The problem I am having in the snow is that the rear tires only spin which activates the traction control and locks up the brakes even when traction is shut off. The front end does not seem to be grabbing. I have owned the truck since 2007 to present. In April of 2013 I had dealer replace ABS brake module. They had some issues programming it. There was no snow until the beginning of winter. Been in and out of dealership 3 times they can't find a problem. Any help would be appreciated. Thanks in advance

 

[ctland08]

Anyone?????