I bought the jeep about a year ago and have not personally done anything to it. when i was getting ready to take the cover off of the diff I took out the fill plug and couldnt see any fluid, or even feel it with my finger through the hole. the fluid was however very very black. I do know that someone has been in there before because there was orange rtv gasket maker on there rather then a normal gasket. I will try to get some pics up today to see if that will help. I really appreciate your help man.