OK, having taken the advice I gave above, I have sent this email to Mark Evans, which I hope he will answer here:
Hi Mark,
There has been some discussion on Talk Morgan recently about the correct filling procedure for the Bevel Box. There is an orange breather [I assume] on the side, that will unscrew and a fill level plug above the drain at the rear.
I think it would be very handy if you would post the correct procedure, for those of us who do our own maintenance, as well as the oil you are currently recommending, and why.
Whilst you are posting, I'm sure it would be appreciated if you could also give an explanation for the problems you and we, have all been experiencing and what you have managed to do about them.
Many thanks,
Paul Jacobs
