Re: C6 Transmission overfill drain valve.

I noticed when i first looked at the transmission oil pan, that there was a large dent (about one square inch) in diameter at the front of the (trans pan) gasket sealing surface, it was as if a large rock had hit it, or maybe someone had hit it hard with a hammer to remove the stuck trans pan-to-trans seal surface/flange. In the worst case scenario, i would worry about a small crack or fracture at the pan sealing surface of the trans. Are these trans cases easily cracked that way? Is the C6 trans case made of steel? I will check the other seals that you mentioned too.