When you have it welded you neex someone who knows welding, alot try 7018 rod but you need more like a 11018 rod, 110k psi rod, after its all welded get a frame insert that fits tight that has 85k tensile strength or higher 1/4" thick and that extends 2 feet either side of repair, if it hits another crossmember the holes are usually slotted enough to fit a sleeve behind it. In other post you mentioned drilling flange, never do that, it is guaranteed to break.