See what Gale Banks has to say about fluid levels in a differential but it will apply to any flooded lube gear system. This is part 1 and 2, part 3 has not been posted yet.

Also dig around on the net to see what Gale Banks has to say about diesel smoke and power.

Do Diff Covers Work or Are They Just Bling? Part 1
https://www.youtube.com/watch?v=n4DQ-jzKQRw


Part 2 of the diff cover / fluid level test. ( there will be a part 3 later )
https://www.youtube.com/watch?v=09JsDorR6tw


No part 3 yet, just a side bar. I'm surprised how much the oil foams up.

What's going on behind your stock diff cover?
https://www.youtube.com/watch?v=9-yG3D3JBRs