I realize this is probably an argument for another thread but I wouldn't really call it a leak, more of a sweat. "Technically" speaking my truck has the "so-called leak" but there's never any oil on my driveway and when I changed the fluid last fall after 1.5 years of having the "leak" my TC still had the correct amount of fluid it it.
My theory is that a drop sneaks pass the seal when you cycle the actuator. A small amount of oil can make a big mess. So you have to use 4lo alot to lower the fluid level. I use 4lo 10-15 times a year and it didn't seem to effect my level.
Just my 2 cents.