s2000maniac

While installing an exhaust today I noticed these small cracks all over the differential housing. Hopefully my diff won't blow out!!

2poor2mod

You're fine. They're not cracks but rather a result of the casting process.

Billman250

Definitely.

slalom44

The Diff housing is die cast. Molten aluminum is poured into a steel die to produce a net shape casting. Over time, the steel die forms fatigue cracks that leave these casting marks. They're actually the mirror image of a crack. They stick out, and don't protrude into the casting.

The reason that Honda didn't reject the casting is because there's nothing wrong with it structurally. These dies are expensive, and if they can get a thousand or so extra parts that have no structural problems, it doesn't cost as much to produce the parts.

You will see these casting marks on diffs and trannies from all manufacturers.

s2000maniac

thanks guys!