Hi guys, i have currently have had a bad problem with rear differentials. My car has 146k as of now but has gone through 2 differentials. Im on my second one right now.

It has developed a bad whine in the diff and am sure it will go at any moment. My question is why am i have such bad problems with the differential??

 

Going through it here as well, I've so far ruled out wheel bearings,fluid & am now focused on the differential output shafts as opposed to the differential itself.