I just changed the axle lube in my 2007 NC3V 3500 and filled with the specified 1.8 liters (Mobil Delvac 75W-90, MB 235.8). This leaves the lube level 1/4 - 1/2" below the fill hole. I searched and found some limited discussion of this in various threads but the responses usually amount to 'I do this' or 'I do that' but there has to be a correct answer. I'm hesitant to fill beyond the specified amount and bringing the level to the fill hole would significantly exceed that. What is correct?