Check them both annually but if there are no leaks visible, the levels will be OK. I might wait another year before changing mine again. Remember that when I first looked at the gearbox oil on mine, after 3 dealer stamps the oil hadn't been checked, because there was no access to the level plug.
Look on my how to post if you haven't read it.
http://www.talkmorgan.com/ubbthreads.php?ubb=showflat&Main=3005&Number=30224#Post30224
http://www.talkmorgan.com/ubbthreads.php/topics/30883/Transmission_oils_for_traditio#Post30883

Hmm. Just read my own advice so it looks like an annual change is needed.

Last edited by DaveW; 13/07/11 07:14 PM.
DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4