it has been reported that Justic brothers gear oil treatment (50 ml) added to primary helps the sound problem from the primary. So after searching locally with no success, I contacted the manufacturer. No problem they said, how many do you need? I , of course said send me 2. Well quess what I receiver, 2 cases not 2 cans. So I have enough to last a lifetime( and probably supply the entire forum). If you would like some, message me and I will send— you pay only shipping. My way of giving back to the forum members who have been so helpful with getting my 961 up and running.