Transfer Case fluid

I have a 2007 GMC Yukon Denali AWD. I am changing out the transfer case fluid and had been informed by the Michell's guide in the maintenance fluid section that it takes the GM autotrack II fluid which is what I used. But after further reading it shows 2 different transfer cases which only one calls for the GM fluid and the other calling for manual trans fluid. Which do I use? And what would be the harm if I used the GM fluid and not the man trans fluid?