Grinding diff slinger???

Here is one more for the modification gremlin files. New gears in the front D30 (High Pinion). New set up kit including pinion seal. Pattern was great on the gears (I saw it after my friend the gear guru set it up)... but on the way home I heard a tinny grinding noise. After I parked, I smelled gear oil, got a half dollar sized puddle under the pinion immediately, and noticed that the color of the new 90 wt was gray. It all looks fine. Could the fluid slinger be rubbing on something? Any gear guys know what it might be? I have to wait until Thursday to crack it open again.

Thanks
HarveOut-

Grey lube is not a good sign. The slinger would eventually put some metal in the oil, but not that quick. Is the grey like a flat grey(cast iron or gears) or glittery looking(brg)?

Gray. I was just looking at it. I hate to talk trash about my gear friend that did the install, but the flippin' pinion seal is in backwards. Would that put the metal face deep enough to rub something? That has got to be it.