TH700 cracked? (welding?)

[germanyvince]

Need advice on this. I'm putting a TH700R4 behind my new GM Perfo block.
Got this used, cleaned it up and thought about a complete rebuild, but first wanted to look at the trans fluid and decide from there on. Now that it's clean i saw some "marks" on the outer case in the bell area. I wonder:
a) are these just panel marks from pouring the aluminum, you know, the lines where the forms are matched together?
b) are these legitimate cracks?

I can't see same lines on the inside.

should i put a tig weld on there, just to make sure? (i'm in the state of a beginner tig welder, but not too afraid to try and lose that, if it's crap anyway...)

https://www.dropbox.com/s/rdxcad8covjulcm/1.jpg?dl=0
https://www.dropbox.com/s/jf7n7rbr6cex9yg/2.jpg?dl=0
https://www.dropbox.com/s/2jfwafi8wbdb8lw/3.jpg?dl=0

 

[ridenby]

Look to be casting marks. Normal.

 

[ktmoutfront]

Yep. What he said.

 

[sweetk30]

x3 on casting lines .

if a true crack it would be seen both sides .

 

[wasted wages]

A good machine shop should be able to magnaflux or zyglo check it if you are really unsure about it being cracked...

but it just looks like casting lines to me also...