Centre diff, gearbox and floorpan sprayed in oil

Continuing my quest to sort the various problems on my 91 Disco 200TDi, I've been looking at the gearbox and centre diff assembly. Pretty much the whole lot (and the floor pan) is drenched in oil. It's a nice trick to reduce chassis rust, but I'm not sure it was designed that way...

There's too much oil to see where it's coming from, but logic says to me somewhere where the oil can be flung everywhere as it makes it's escape.

Where should I look in particular?

Cheers!

Malcolm

hi it will either be the transfer box seals,1 on the front prop from transfer box or seal inside handbrake drum both pretty easy to do,tiga