Leaking Pinon Seal

[crsgmc]

When I purchased the truck the pinon seal was weeping, not enough to drip so I worked on other problems. Now the seal went from weeping to leaking. I purchased a new yoke (USA standard gear)and AC Delco triple lip pinon seal. The yoke had an extra collar with it that I think is to be used with the newer triple lip seal. I also replaced the back two U joints. Everything went fine and after the repair I drove the truck about ten miles and it is still leaking. I checked the vent hose to make sure it was pressuring the differential as the oil heats up. The line was clear. It is not leaking a lot. Do you think that it might wear in and stop leaking. When I installed it was around 30 degrees so maybe it is just stiff. I am probably wishing on the problem going away. I guess I will tear it apart and try another seal, not sure what else to do. Anyone have any suggestions why it is still leaking? I did a lot of internet searching but nothing was real helpful.