fluids

Hi All, I'm a new member of this forum, I'm looking to learn how to change the real differential fluid on my 2012 Altima 3.5 SR. I have used Google and You Tube the last few days but found no luck on this subject. I spent some time today looking under the car and could not locate the area...

The first time I got the oil changed (I've owned this car 4mos) the oil showed a quart low on the dipstick I got it changed checked it again they had filled it perfectly, I've been checking it every couple weeks and it showed no sign of going down I check it 2 days ago it's a quart low, I check...