pulled the box...
cause: not fill-welding around the sleeves...under the ear that cracked was about an 1/8" depression that the ear pulled into after 9ys :p
well, duh...
the opposite side was the same but hadn't cracked.
I filled the two depressions in and ground the surface flat and am having the box repaired by a local guy who has done a lot of cast.
should be good for another 9yrs :p
ironically I could probably have just done the repair to the plate mount...welding/grinding flush and then remounting the box and torquing it down...probably would have lasted longer than the truck will.
