Dis-assembled both gear boxes. Deburred, scuffed and primed all sides of both gear boxes. Riveted fwd and aft bulkheads onto gear box angles. Riveted bottom angles, Clecoed box web onto both gear boxes. Bolted weldments onto both gear boxes. Torqued all bolts. Removed one rivet on each gear box that should be installed when the mid cabin brace is installed later.