I got a 518 and a 618. I'm going to beef this trans up with the internals of the 618 into the 518. Well the 618 tail shaft was missing on the trans when I got it.

My question is the shaft that hangs out of the back of the trans. The one out of the diesel looks to have been worked on. Should I use it? Here are some pictures of it.

I think I read somewhere that you want the holes bigger, but..............

Tell what you guys think, please.