Recently I acquired a 8.8 rear end. Was informed that gears had been replaced in said rear and were used for 10-20k miles. Got home and tore into it only to find what I believe is a cracked housing. Can anyone confirm? Is it useless at this point?

There’s what appears to be a very noticeable crack between the top oil return port and race sleeve as well a less noticeable pit inbetween the bottom. The race sleeve itself is undamaged but reaching in the ports I noticed the suspected crack goes back in the housing.

 

"Can anyone confirm? Is it useless at this point?"
IMO the crack will propagate diametrically across from the present crack, resulting in failure of the whole works. I have seen cases where the entire carrier casting was cracked entirely in two, due to gear failure. I would not risk it.

 

Upon further inspection with just the eye and a flashlight I’m now question my original statement. Is there a chance that this could just be an impurity in the casting process? I see no visible split, but more of a thin indentation that just happens to appear to be a crack looking at it dead on. I don’t have a microscopes to get a closer look but I suppose I should probably take it in to have it inspected.

 

Exactly what I was wondering, No evidence of a leak of fluid from there so perhaps just a casting line?