frame repair
The crack in this case is most likely the result of loading from the shock absorber. Or overloading to the point that the axle bumps the frame. Consider the fact that even with the crack, the truck has not fallen apart. I have spliced heat treated frames and if the work is done correctly, it will hold up.
There was a post a while back about rusting through at the tank mount bracket. If significant rust is your delima, I have a frame for a regular cab dually that I will sell or swap for something I need should that be of any help. It is complete less the engine, transmission, and rear axle. Sell/swap all or part.
For R. Guzzo. Did you get my PM regarding your transmission? My listing does not show that any message has been sent.
James