The rib running the lenght of the axle tube, is it a weld or something else to do with the way they were shaped? I was thiinking of grinding them smooth but I don't want to do that just to find out that it will weeken the housing.

On another note. You can sure tell that back in 79 they didn't have robots doing the welding. I ground down some of the globs of weld and found very poor welding. There were holes in the welds from someone welding over flux.

 

I wouldn't grind on the axle tubes. Removing any material will result in some loss of strength. Without looking to make absolutely sure, I'm almost positive what you are talking about IS a weld that joins two halves of the tube.

It isn't all that uncommon for the axle to leak gear oil because of poor welds, even in later model axles. Pinholes in welds used to be fairly common.