Well I called my dealer today and they acted like I was crazy! Told me it would be a week before the could even look at it and up to two more week to find problem and then they would order parts.
So I put my X on the (4 so it's level) stands and pulled the plug for rear diff and took a Qtip bent at a 90 deg and stuck it in. Guess what? It never touched oil,250 miles and no oil. Man I'm pissed called the dealer and talk to GM and told him to ask the kid who put my unit together how much oil he added to front and rear diff.
No back out to check front and gearbox.