Pinion Seal Question

I've never saw one that wasn't painted either but I don't rely on the paint to seal it anyway. I use a thin layer of shelac on it.

Now onto your leak:

Have you verified where the leak is actually coming from? If you haven't verified where the oil is actually coming out of do so before you disassemble it. It can not only leak from between the seal and yoke but it can also leak from between the seal and housing and can even leak out between the pinion to yoke splines. If it's leaking from the splines use a little rtv on the splines when you assemble it. If it looks like it's coming out between the yoke and seal inspect the yoke very carefully when you remove it to make sure there isn't any sign of a groove worn where the seal rides. Sometimes it doesn't take much of a groove to cause a leak. If there is you need to either replace the yoke or install a speedy-sleeve. If it looks like its coming otu between the seal and housing seal that area with shellac when assembling like I mentioned above.

Verify'ing it before you tear it apart may save you from doing it all over again.

One last thing, doesn't the 8-1/4" use a crush sleeve to set pinion bearing preload? If so removing the yoke can disturb the setting and cause mechanical issues. I always replace the crush sleeve with a solid spacer and shims so if I have to take it apart again it doesn't disturb the setting.