Hey guys so I have a scraper that we recently put a new differential on and it’s constantly leaking from what I think is the breather? It’s a black knob that’s dead center of it and when you put it in 1st or reverse it leaks. But doesn’t in neutral. Why is that? The vin is T0762BX804008. Any advice or ideas would be gratefully. Even a way to possibly trouble shoot it. Maybe my coworker hooked up a line wrong? Thanks in advance