so I was driving the rig in signature today, went over a patch of ice and hit the gas to spin the tires, fun stuff.. do it all the time. well when the moving tire went from the ice patch to the dry pavement I heard a nasty sound.. the rear end felt odd.. luckily I was 30 seconds from my garage, pulled it in jacked it up.. so I have a block lift kit that includes front and rear spring lifts as well as a 3 inch block for the (3rd member?) for the rear. the thing that's shaped like a C that bolts to the top of the diff. well turned out that I sheared off all 4 bolts into the diff!!!! and to make things worse.. when I installed the kit I was in a bind for time and resources and used bolts that were of the wrong threads. so I just spent 2 hours trying to get out the one that ican get to with heat and vice grips.. not happening. I don't know what to do at this point.. the rig is to nice/modded to trash. the underneath is to rusty to even think about removing the rear axle. soo was thinking maybe I can have a machine shop duplicate the lift block in steel and I could weld it in? only issue and this is main reason posting..is the diff and the rectangle piece with the baljoint that bolts to the top of diff made of cast iron? see what im getting at? please any suggestions! most of this rig is jimmy rigged anyway so im up to almost anything that would attach point A to point B with the spacer in between.