Front Diff Leak? How much to fix?

[FlaskTL]

This afternoon I was changing my oil and I decided to drop the skid plate as I thought it would be easier to drain the oil. When I dropped it I notice that the diff is wet looking and that the frame where the skid plate mounts to is also wet. Def oil. I took some pics on my iphone that I am going to try and attach. How much is this going to cost to fix? I was just about to buy a Black Bear tuner in hopes of turning of my AFM and fixing the oil burning problem. Are diff leaks common in these trucks?

First photo shows the wet diff. The second photo shows the diff but at the top of the photo you see the frame where the skid plate was mounted to was also wet. Could this be splatter from past oil changes? ( a hopeless question I know) How can I fix this without breaking the bank fellas?

[ruggedlife]

does it smell like gear fluid? you can check the level.. its not HATEFUL if you know what you're doing. but for a weekend warrior it could be a big can o worms