The tranny is sealed tho most have pour spouts to add it. The 5 cyl auto on the 06 is a nightmare tho. It doesn't have a pour spout. Idle the car for 5 minutes, remove drain plug, ( if at right temp nothing should come out) insert special pump connector into drain hole, connect to pump, connect pump to tranny fluid container and pump away. Remove pump. At temp only excess should flow out. When it just drips slowly it's full. Insert drain plug.
If the smell is only happening when the car is cold then it is the fuel pressure regulator. I had this issue for more than a year in my 2000 grand am Gt before my mechanic saw it and fixed it. (Not his fault - mine). It's a $75 - $80 part if you buy it. + labor if your mechanic installs it.