Good points thanks - will check them out. I can see a smear of oil down the diff from the filler plug after a run and drips collect at the bottom, which made me think it was coming from there and they were getting caught in the airflow and curling up behind the tail end. The spotting seemed to get worse after I replaced it with a new plug. Wanted to try anything you guys could recommend as a good thread sealer first.
There are also drips on the bottom bolts on the transfer box plate and I am trying to work out where they are coming from. Drips happily when hot during a run, but stops within a minute or so of stopping...which is a pain when you're trying to clean it and look for evidence of a leak !
Sparky