Again using the open hole in the collar, drill through the TT and into the input
shaft with the #46 drill bit, creating a divot. Again disassemble and inspect the
divot to ensure it’s deep enough for the setscrew to set into it.
Reassemble the parts, and loctite a 3X3 setscrew into the hole with the divot,
then the remaining 2 setscrews. Remove the 2 ea 3X4 SHCS from the gearbox
then slide it into the tail boom, lining up the holes for the Bolts. If they don’t
quite line up, rotate the gearbox 180 degrees and try again.