Cracked bellhousing

Hey guys, and girls.. I scored a 727 trans connected to a 318 for small money, I always wanted to dIY a trans upgrade, so I installed the reprogramming kit in the VB and disassembled the case, as I was power washing I found a 3 to 4 inch crack next to the line up stud on passenger side of bell housing. Question is I want to try and repair myself but I don't know what works well with aluminum. I have a mig welder with 25/75 argon or should I try the propane and stick or jb weld or should I bring it to someone who may or may not do it right.. What are your thoughts?