Hi Girls,
You did not say which seal was leaking, if it is one that goes to a front propshaft, then a relatively easy job, you will need to drain the transfer box oil first. The nut in the centre of the flange will be tight but if the other shafts are on, then the flange will not turn. You may need a pluller to remove the flange, but cross that bridge when you get to it, it may come off with a slight tap, there is a split pin securing the nut. Once the flange is removed, the seal housing can be unbolted and seal removed and new one fitted. Make sure there is no rust or mark on the seal path of the flange. If you have to change a seal on a rear one as well, the practise of doing a front (easy), will help.
best of luck
regards, Richard