Drive train noise

[wold racing]

I drove the SVX to MN form FL with the fuse in so that it stayed in front drive only. I took the fuse back out when I got to MN and the rear diff noise seems to be a bit better.... No noise in a straight line.... Turning right or left while going forward, there is very little noise.... Turning right or left while going backwards and you can hear clunking.... Noise just like you are pushing a race car while turning with a LSD or locked rear end ..

I was looking at the manuals and it shows the diff uses typical gear lube on the final drive side of the diff and that the LSD side is "sealed", whatever that means... If it is sealed, what is the lubricant and how does it stay sealed??

Has anybody seen a good article on how the rear diff works and any ideas on why