Yep I was taught in high school auto shop in 1973 to always fill rear ends and manual trans to about a 1/2" below the plug. Up to the rear end plug actually has to much oil run out in the axle tubes and gets at the axle seals. Even bearings that get the diff lube get plenty when filled 1/2" below the plug hole. I remember my shop teacher saying if you fill it to run out the plug hole its to high as it will raise even more when the fluid gets hot. Ron