THREE EMPLOYEES WERE REPLACING THE PLANETARY GEAR DRIVE SET INTO THE HUB/DRUM OF A CAT 992C LOADER. THEY WERE USING THE OVERHEAD CRANE TO LOWER THE DRIVE SET INTO PLACE & POSITION & ALIGN THE SET INTO THE GROOVES VERTICALLY. INJURED ROTATEDONE OF THE GEARS JUST AS THE SET ALIGNED INTO THE GROOVE NEAREST HIS LEFT HAND. THE WEIGHT OF THE GEAR SET PINCHED HIS LEFT MIDDLE FINGER TIP.