D-Sport

hi guys, my diff ran out of oil due to the back casing getting damaged by the sliding ramps underneath rubbing off it, it could have ran for 60 to 100 miles without oil and the diff when i got home was very hot, i fixed that problem yesterday and filled it back up with oil but this morning i found a few splatters of oil coming from the front of the diff (on the garage floor) where the drive/ prop boolts on, im guessing there is an oil seal there and if f***ed, can it be changed? or is it a new diff or will it be ok and just need a fill of oil every now and then, the van is a 98 transit recovery and doesnt get used very often only to ferry a cosworth around ireland to track days etc. all help very much appreciated