Trying to put my new to me 3.9diff in my 4.3 housing tonight. Was cleaning up the housing to install the diff carrier and noticed these cracks. They don't go all the way through and are barely noticeable to a fingernail. Should I be worried? Or is this a normal thing?

 

Casting flash. You'll find it all over the oil pan too. No concern at all.

 

Thanks. Didn't want to call and bug ya. Figured that's what it was. Wanted to double check in case of.

 

^What he said.

You see the same thing in aluminum engine blocks all the time.

 

I'd love to open the hood of my car and see aluminum casting flash on my block, instead I have this iron ****.

 

Actually I'd much rather see a high flowing head on our engines instead of an aluminum block.

Look at the 4g63: iron block closed deck and raping face basically embarrassing 80% of the other 4 cylinders in the world

 

Given the average HP numbers of a 4g63 it may as well be a V8.

 

get one of those semi-hard buffing wheels throw it on a drill and clean those off if it bothers you. Doing that should make it less prone to cracking. Exactly how less prone? Could be anywhere between not much and allofit.

 

So glad you all posted this. I just cleaned up a 4.10 Torsen and found the same "cracks" and was very concerned. Thanks! Now I feel comfortable proceeding.

Eric
'92 Black & Tan

 

Adapting a race casting 91mm c-c head?
www.motordesign.se
I'm too cheap to even ask them, the exhaust on the other side would be a minor problem.