wow ,sorry to hear that.hope he gets well soon .txarc ,i had this happen to me when i was 16,i was pulling the tranny and did exactly what you said ,shook it off the pins and the stands were unsteady .car dropped on me and broke both arms and sternum.i was lucky,i guess.i put my arms up too stop the fall on me ,didnt work ,i came out looking like edward scissor hands.Be careful guys ,o also dont use scissor jacks either.
mods:2004 sierra ext sb,20s ,big brake kit w,hawk pads,air bagged,2006 6.0 lq4 swap,vortec supercharged10psi, air to water intercooled w/ dual electric fans on it ,snow meth injection kit,60lbers, e-fans ,big radiator swap ,cam 218 /222 548/550 comp .hardened prs .1.85 comp roller rockers ,guideplates ,crane double springs,trans 4l65e built .pacesetter l/ts true duals w/x pipe and magnaflows,14 bolt rearend swap ,3.73s,aroemotive fuel pump system w/elec.fuel controller and bypass regulator a/n fittings, taylor 10.5s interceptor gauge,aem w/b a/f ,autometer boost/vac NELSON 93 OCTANE TUNED .