My manual says that the oil in the differential should be a specified level below the drain plug but then does not say what this level is. Does anyone know?

I could just fill with specified volume but will still be some old oil left in.

Thanks Greg

I think most people on here would say to fit it then fill it untill it starts coming out the filler hole. I did this on my 1st build because Mark Evans did it on his Westfield so i guess it must be ok.

10mm below, (lubrication specifications, page 203, haynes book 903 (turquoisey one)) but i'd just fill it to the level of the plug.

hth
tom