I've been driving pickups for 35+ years and 4x4's for 20. Recently acquired a 2004 Yukon Denali with AWD and am having some issues. Is there any way to keep it locked in??? Just snowed 12" of wet heavy snow and I'm trying to back up an incline. Spins, locks in, grabs traction, kicks out, spins ... stuck. Go forward. Try again. Repeat. Couldn't keep it pinned or I would have launched out of an alley THIS is gonna get old ... quickly. Anyone can give me some pointers on how to drive an AWD? I will be most appreciative!