Am I reading correctly, 400,000 wt oil.

I have a 3racing geared diff fitted. After a few months of running it loosened up to the point I thought I was losing pace. I replaced it with 100,000 wt oil and the car became undriveable for me. Coming out of corners on good grip tarmac it would dive off to the side without any warning. It was really really thick stuff. Cant imagine 400,000wt is anything other than locked.

Have 30,000wt in now and 40,000wt if that loosens up too much.