They have that grape scented diff fluid.
When i went to change the rear diff and transfer case fluid in my wifes awd, that smell confused the crap out of me.
IIRC the color was a little off too.
I was more worried about the AWD xfer case, since i read it was 75/90...
Like the Tahoe, I read it was autotrack 2 fluid, so i ran with that.
xfer case was not happy at all with autotrack 2 fluid.
Did not like going in and out of engagement and would throw codes.
I had to reset the codes before it would try again.