Expansion Valve Question
This is probably something you shouldn't be doing.
But. The female end of the TXV screws fast to the male end of the piston holder. After you remove the piston.
The male part your referring to, is the external equalizer, that must be tapped into the suction manifold, or line. Preferably inside the evap coil cabinet.
Is the coil a match to the outdoor unit. Or is it a mismatch system. Just because the coil is rated at the same tonnage as the condenser, doesn't mean its a matched system.