Small transmission scare

So I figured I'd check the oil level in my transmission, considering I'd noticed that the back of the housing's been pretty wet...

So I put Liesel up on jackstands and took out the filler plug.  Normally, the oil level is supposed to be flush with the bottom of your finger.  However, as far down as I was able to reach, there was nothing...  So I pulled her off the jackstands (to allow for level ground and all that), STILL NOTHING!!  

The only thing I've noticed so far during driving, however has just been that the transmission is a tad louder when completely cold, but that noise goes away when it warms up.  In order to play it safe however, I left her at home today, will fill up fluid (and possibly add leak sealant) and then take her out again...

Will also monitor for rate of leakage, I know I'm going to have to replace the output shaft seal sooner or later...