Hairline cracks in NP231 case

While installing my Tom Woods SD SYE, I noticed a few hairline fractures in the case (both front and rear halves):





There are no leaks or anything, and I seem to find occasional references to similar fractures in other peoples' cases that seem to be rationalized as side effects of the casting process.

Has anyone else noticed similar cracks in their case? Am I risking a failure with this? I ran the vehicle for nearly 1,000 miles with pretty bad driveline vibrations, but had never opened the case prior to installing this SYE so I don't know whether or not they're related.

Any input would be appreciated. Thanks guys!

They aren't cracks. Just surface imperfections caused by casting.

X2,no cracks there!

Rock on. Thanks guys - I was really afraid of needing to do this job twice.

One other question, though - when installing the oil pump over the new main shaft, it did anything but slide onto it (unlike removal, in which it basically fell off). I ended up lightly tapping it (alternating from one side to the other) with a screwdriver and hammer until it was fully seated... Is this normal?

This is what a cracked 231 looks like... those are just beauty marks.

Ouch! That looks... gnarly. Got a story to go with that?

Yes, unfortunately. Front driveshaft bolts came loose, and finally snapped.... in my driveway of all places. I heard a odd noise, and thought it would be wise to put it in 4 wheel drive in my gravel drive way to see if the noise changed... turns out it was NOT wise to do that. The added torque finished off the one or two bolts barely holding in the driveshaft, and then it got bound up between my floor panel and the yoke of the t case. the t case lost the battle. Happened in about 2 seconds.

But its not the end of the world, i was able to replace it with this, so all is well. NP 241OR
Rocktrac.