I just recently changed the fluid in the rear differential of my truck and unfortunately the next day I noticed it was leaking. It appears as if it is leaking from the seal because the housing is dry. I changed the fluid using Mobil 1 75w 90 gear oil and I replaced the gasket and used black rtv sealant. Anybody have any ideas? My truck is a 2001 Silverado 1500 LS 5.3L 2wd. It has the GT4 differential. It asked for 2 1/4 quarts and I may have put in slightly more than that, but not by much. It was still under the fill hole and the additional amount wasn't much.

Thanks in advance for the help!

 

pinion seal leaking probelm wore out or a groove wear in the york where the seal ride

 

I should add that it was not leaking before I changed the oil.