the local carby coure does not use a TCM to shift - the jap ones do, just like the G100 charade had - a small box to control the 2 shifting solenoids to select all speeds.
The transmission found in our indus motors cuore is quite different from the ones you will source at the junkyard - as our local cars use 0.85 litre carby engine hence use a transmission with a lower final drive, larger clutches and a more robust torque convertor that locks up solely on governor pressure, unlike the ones you get on a turbo 660 with solenoid shifting and lower top speed with a weaker torque input at lower revs
IMO it will be hard to find a serviceable 850cc hydraulic controlled cuore transmission as nearly all are installed in cars and none are being imported in junk.
Its better to stick with what you have until you can find a nice working transmission. To swap is very easy.
The parts required are
and finally remove dashpot from carb to induce engine braking on overrun