R380 LEAK

swapped my transfer boxes today lt230 for one i've rebuilt , i was going to change the r380 output seal but as it was bone dry in between the 2 boxes and not having the special tool i felt best left .
But where the box joins to the alloy section , oil is running down what looks like from above , Any ideas please what this could be and where its weeping from .

Ok so looked at this leak again . It certainly does look like its leaking down from above . There is no leak at least so far from the intermediate shaft o,ring all is bone dry , Nor from the drain thats between the 2 boxes if the seals had failed , Even if it were those as well it would not leak from up top . Would it ?.
Its dripping down From Above and onto the bottom of the gearbox at the joint between the extention case and gearbox , .
What is it likely to be ?? , someone said the o'ring in/on ? the selector shaft housing on top of the gearbox . If so would this really leak that bad . Its all wet behind the gearbox mount bracket and up above in that general area . I've seen pictures of an R380 which looks like oil is ouzing out the top of the gearbox , but there's no write-up on it .
My Plan is to remove the transmission tunnel , (unless I don't have to) and replace said o'ring or gasket to cure this leak , But i dont know what to order to fix this and i want everything there ready fof when i do .
Any help would be very helpful , thanks gerry