Hi, There is a few seals on these gearboxes, one for each driveshaft, one for the input shaft and small gaskets on boot holes and selector shaft. More than likely it will be driveshaft seal as these are the most common to go, you will have to wash the the box down and monitor where the oil comes from. If it's a driveshaft seal then you wont need to remove the box, just drain the oil and remove whatever shaft it's leaking from. If you are in need of seals I sell them in my online shop, just follow the link in my sig Hope this helps Gary