I started cleaning my transmission to do a rebuild.  As I cleaned it I noticed the case is very, very orange peeled.  The case looks like aligator skin.

I'm assuming you have an automatic. Some of the cases were really nasty when new. It has to do with the amount of leftover aluminuminum in the molds when the cases are cast. When the molds are clean, the cases come out super nice, and smooth. Once the molds build up a little "s l a g" on them, the outsides of the cases start to get really rough. It's not a problem at all, as far as usability, or functionality. It's all cosmetics.
(I hate handling those cases...they are so rough, they hurt my beautiful, dainty hands. )
There should be no issues with the porosity of the case, due to the molding s l a g. I've seen some that actually had pieces flake off, like a bit of oyster shell. It's still not a problem...they just look like crap. Not something you would want to put in a T-bucket, or show car, that's for sure!


Wow...when did "s l a g" become a derty werd? The software changed it!!Adams' Apple2007-02-24 16:46:40

Thanks for the information. 

One of the amin reasons I got rid of my TH400 was the pan area was real bad. The porosity was so bad that no gasket would seal for more then a couple of weeks. I have changed filters in many trans through the year and never had the problem I had with that trans. The guy I gave it to is still having the same problem with it. The only thing I didn't try was recutting the surface but thats all history now. Hope yours is a lot better then mine was.